EXHIBIT 10.6



                               AGREEMENT OF LEASE

                                     BETWEEN

                            JOSHUA REALTY CORPORATION

                                       AND

                        AMERICAN MANAGEMENT SYSTEMS, INC.





                               AGREEMENT OF LEASE
                              CENTERPOINTE I AND II
                                FAIRFAX, VIRGINIA

                                TABLE OF CONTENTS

1. Reference Data and Definitions............................................1
2. Demise of Premises........................................................4
3. Term......................................................................4
4. Possession................................................................5
5. Use of the Premises.......................................................6
6. Base Rent.................................................................6
7. Additional Rent...........................................................7
8. Late Charge; Interest....................................................14
9. Services.................................................................14
10. Repairs and Condition of Premises.......................................19
11. Compliance with Law.....................................................19
12. Estoppel Certificate....................................................20
13. Rules and Regulations...................................................21
14. Assignment and Subletting...............................................21
15. Alterations.............................................................24
16. Mechanics' and Other Liens..............................................25
17. Landlord's Right to Enter...............................................26
18. Certain Rights Reserved by Landlord.....................................26
19. Landlord's Liability; Rights............................................28
20. Unilateral Amendment....................................................29
21. Insurance...............................................................29
22. Fire or Other Casualty..................................................30
23. Waiver of Claims; Indemnification.......................................32
24. Condemnation............................................................33
25. Holding Over............................................................33
26. Covenant of Quiet Enjoyment.............................................34
27. Relocation of Tenant.  Intentionally Omitted............................34
28. Condition of Premises...................................................34
29. No Third Party Beneficiaries............................................34
30. Transfer of Landlord's Interest.........................................35
31. Default; Landlord's Remedies............................................35
32. Remedies Cumulative.....................................................38
33. Expenses of Enforcement.................................................38
34. Nonwaiver...............................................................38
35. Subordination...........................................................38
36. Paramount Lease.........................................................39
37. Legal Proceedings. .....................................................40
38. Interpretation..........................................................40
39. Severability............................................................40





40. Notices.................................................................40
41. No Representation by Landlord...........................................41
42. Whole Agreement.........................................................41
43. Security Deposit.  Intentionally Omitted................................41
44. Real Estate Broker......................................................41
45. Inability to Perform....................................................41
46. Corporate Entities......................................................42
47. Recordation.............................................................42
48. Time....................................................................42
49. Applicable Law..........................................................42
50. Defined Terms...........................................................42
51. Delivery for Examination................................................44
52. Environmental Matters...................................................44
53. Tenant's Remedies.......................................................46
54. Extension Option........................................................47
55. Signage.................................................................49
56. Storage Space...........................................................49
57. Food Service In Centerpointe II Building................................50
58. Non-Disturbance.........................................................50
59. Exercise Room...........................................................51
60. Parking.................................................................51
61. Right of First Offer....................................................51
62. Expansion Space.........................................................53
63. Measurement of Premises. Intentionally Omitted..........................54
64. Tenant's Affiliation Representation.....................................54
65. Arbitration.............................................................54

        Exhibit A-1.                 Plan of Centerpointe I Premises
        Exhibit A-2.                 Plan of Centerpointe II Premises
        Exhibit B.                   Landlord's Base Building Modifications
        Exhibit C                    Tenant Design and Construction Process
        Exhibit D                    Concession Fund Voucher Form
        Exhibit F                    Rules and Regulations
        Exhibit G                    HVAC Standards
        Exhibit H                    Legal Description of the Property
        Exhibit I                    Index of Defined Term
        Exhibit J.                   Form of Lease Memorandum





                               AGREEMENT OF LEASE
                              CENTERPOINTE I AND II
                                FAIRFAX, VIRGINIA

         This Lease is made this 10th day of August, 1992, between JOSHUA REALTY
CORPORATION, a Delaware corporation, (general partner and sole remaining partner
of Faircenter Limited Partnership, a Delaware limited partnership)(hereinafter
referred to as "Landlord"), and AMERICAN MANAGEMENT SYSTEMS, INC., a Delaware
corporation, (hereinafter referred to as "Tenant").

         1.        REFERENCE DATA AND DEFINITIONS:

         ANY REFERENCE IN THIS LEASE TO THE FOLLOWING SUBJECTS SHALL INCORPORATE
THEREIN THE DATA STATED FOR THE SUBJECTS IN THIS ARTICLE 1.

                   1.1.    DEMISED PREMISES

                   (a)     SPACE DESCRIPTION - CENTERPOINTE I: Approximately
                           203,630 rentable square feet on eleven (11) floors of
                           the building ("Centerpointe I Building") located at
                           4050 Legato Road, Fairfax, Virginia and commonly
                           known as Centerpointe I (the "Centerpointe I
                           Premises") as shown on Exhibit "A-l" attached hereto.

                   (b)     SPACE DESCRIPTION - CENTERPOINTE II: Approximately
                           38,384 rentable square feet of space on the third
                           (3rd) and fourth (4th) floors of the building
                           ("Centerpointe II Building") located at 4000 Legato
                           Road, Fairfax, Virginia and commonly known as
                           Centerpointe II (the "Centerpointe II Premises") as
                           shown on Exhibit "A-2" attached hereto.

                   (c)     RENTABLE AREA OF THE DEMISED PROMISES: The
                           Centerpointe I Premises and the Centerpointe II
                           Premises are herein together defined as the
                           "Premises" and the Centerpointe I Building and the
                           Centerpointe II Building are herein together defined
                           as the "Buildings". The exact square footage of the
                           Premises has been measured in accordance with the
                           Washington, D.C. Association of Realtor's Standard
                           Method of Measurement (January 1, 1989). This figure
                           shall be used for all purposes under this Lease,
                           including, but not limited to, determination of Base
                           Rent and Additional Rent.

                   1.2.    Base Rent: Thirteen Dollars and Seventy Cents
($13.70) per rentable square foot, net of Electricity Costs (as defined in
Article 7.1.3), and subject to adjustment as described in Article 6.3 below.





                   1.3.1.  BASE YEAR OPERATING EXPENSES shall mean the Operating
Expenses (as defined in Article 7 below) incurred by Landlord during the
calendar year 1993, as adjusted pursuant to Article 7.4.4 below.

                   1.3.2.  BASE YEAR REAL ESTATE TAXES shall mean the Real
Estate Taxes (as defined in Article 7 below) incurred by Landlord during
calendar year 1993 (as the same may be adjusted pursuant to Article 7.1.1(e)
below).

                   1.4.    RENT COMMENCEMENT SCHEDULE: Tenant shall commence
Base Rent payments for the Premises in accordance with the schedule below.

                    Rent
                    Commencement Date                 RSF
                    -----------------                 ---

                    (a)  December 1, 1992             70,451
                    (b)  May 1, 1993                  38,336
                    (c)  August 1, 1993               38,336
                    (d)  November 1, 1993             38,384
                    (e)  May 1, 1994                  56,507


                   The space described in Article 1.4(a) above is herein defined
as the "Initial Space" and the space described in Article 1.4(b)-1.4(e) is
herein defined as the "Subsequent Space". The dates in Articles 1.4(b)-1.4(e)
under the column "Rent Commencement Date" are each herein defined as a
"Scheduled Rent Commencement Date".

                   1.5.    CONCESSION FUND:  $28.50 per rentable square foot.

                   1.6.    SECURITY DEPOSIT:   None

                   1.7.    STANDARD BUILDING OPERATING DAYS AND HOURS:

                           (a)       Centerpointe I Building:

                           8:00 A.M. to 7:00 P.M. Monday - Friday
                           8:00 A.M. to 1:00 P.M. Saturday

                           (b)       Centerpointe II Building:

                           8:00 A.M. to 6:00 P.M. Monday - Friday
                           8:00 A.M. to 1:00 P.M. Saturday


                                       2



                   1.8.    PERMITTED USE: General office use, and uses
incidental thereto (including, without limitation, the conduct of computer
operations and the use and operation of all equipment related thereto).

                   1.9     (a)     ADDRESS FOR NOTICES TO TENANT:

                                   American Management Systems, Inc.
                                   1525 Wilson Boulevard Suite 130
                                   Arlington, Virginia 22209
                                   Attn: Mr. Thomas W. Huba

                                   with copies of notices at all times to:

                                   Shaw, Pittman, Potts & Trowbridge
                                   2300 N Street N.W.
                                   Washington, D.C. 20037
                                   Attn: Craig A. deRidder, Esquire

                           (b)     ADDRESS FOR NOTICES TO LANDLORD PRIOR TO
                                   LEASE COMMENCEMENT DATE:

                                   Joshua Realty Corporation
                                   c/o LPC Commercial Services, Inc.
                                   4050 Legato Road
                                   Fairfax, Virginia 22030
                                   Attn: Mr. Michael Taylor

                                   Address from and after Lease Commencement
                                   Date:

                                   c/o LPC Commercial Services, Inc.
                                   4000 Legato Road
                                   Suite 950
                                   Fairfax, Virginia 22030
                                   Attn: Mr. Michael Taylor

                                   with copies of notices at all times to:

                                   Lincoln Property Company
                                   1530 Wilson Boulevard, Suite 200
                                   Arlington, Virginia 22209

                                   Attention: Mr. John B. Grissim



                                       3


                                   and

                                   General Electric Investment Corporation
                                   3003 Summer Street
                                   Stamford, Connecticut 06904-7900

                                   Attention: Mr. Steven D. Burton

                                   and

                                   Wolf, Block, Schorr and Solis-Cohen
                                   12th Floor Packard Building
                                   15th and Chestnut Streets
                                   Philadelphia, PA 19102

                                   Attention: Alvin H. Dorsky, Esquire

         2.        Demise of Premises. Landlord hereby leases to Tenant, and
Tenant hereby hires and takes from Landlord, the premises identified as the
"Premises", for the Term (defined below) and subject to the covenants, terms,
provisions and conditions of this Lease, together with the right to use, in
common with others, of all common and public areas in the Buildings including
(without limitation) elevators, stairways, lobbies and corridors in the
Buildings necessary for access to the Premises (provided, however, that subject
to Landlord's right to entry hereunder, use of the common areas of the
Centerpointe I Building shall be consistent with that afforded to a single
tenant building during the time that Tenant is leasing one hundred percent
(100%) of the rentable area of the Centerpointe I Building).

         3.        Term.

                   3.1.    The term (the "Term") shall commence on the date of
this Lease (the "Lease Commencement Date") and shall end, without the necessity
of notice from either party to the other, on November 30, 2007 ("Termination
Date").

                   3.2.    The Term shall commence as to each segment of the
Subsequent Space on the earlier of (i) the date which is four (4) months prior
to the respective Scheduled Rent Commencement Date for such segment of the
Subsequent Space or (ii) the date that Tenant or anyone claiming under or
through Tenant first occupies such segment of the Subsequent Space (each such
date which is the earlier of (i) or (ii) above is herein defined as a
"Subsequent Lease Commencement Date").

                   3.2.1.  Tenant's obligation to pay Rent (defined in Article
1.2) for the Initial Space shall commence on December 1, 1992 ("Rent
Commencement Date"). All other obligations of Tenant pertaining to the initial
Space under this Lease shall commence on the Lease Commencement Date.



                                       4



                   3.2.2.  Tenant's obligation to pay Rent for any segment of
the Subsequent Space shall commence on the Scheduled Rent Commencement Date for
such segment of the Subsequent Space (each such date is herein defined as a
"Subsequent Rent Commencement Date"). If Tenant occupies any segment of
Subsequent Space for the Permitted Use prior to the Subsequent Rent Commencement
Date for that segment of Subsequent Space, then Tenant shall pay to Landlord an
amount equal to Five Dollars ($5.00) per rentable square foot per annum, in
equal monthly installments in advance, as Additional Rent hereunder for each
such segment of Subsequent Space from and after the date that Tenant occupies
and uses that segment of Subsequent Space for the Permitted Use until the
Subsequent Rent Commencement Date for that segment of Subsequent Space. All
other obligations of Tenant pertaining to each segment of the Subsequent Space
under this Lease shall commence on the respective Subsequent Lease Commencement
Date.

                   3.3.    The First Lease Year shall be the period commencing
on the Rent Commencement Date and continuing through December 31, 1993. Each
Lease Year after the First Lease Year shall be a consecutive twelve (12) month
period commencing on the first day of the calendar month immediately following
the preceding Lease Year, except that the Last Lease Year shall be the period
from the first day of Tenant's partial Lease Year occurring at the end of the
Term until the Termination Date.

         4.        Possession.

                   4.1.    In addition, to the extent required by law, Landlord
will comply with the requirements of the Americans With Disabilities Act of 1990
("ADA") requirements applicable to the "Core Elements" of the Buildings
(including those which may arise because of the performance of the Tenant Work)
and Tenant shall comply with all other ADA requirements respecting the Premises,
including those requirements arising from Tenant Work. The "Core Elements" of
the Buildings are defined as the roof, the ground floor lobby or lobbies,
entryways, the garage, surface parking areas, paths of travel to and from the
Buildings, loading docks and loading zones, elevators and elevator call buttons,
stairways, risers and other penetrations, restrooms and drinking fountains not
installed by Tenant in connection with the Tenant Work, or otherwise, and the
base-building mechanical, electrical, HVAC and plumbing systems (excluding any
changes thereto or extensions thereof performed as part of the Tenant Work or
any later Tenant alteration).

                   4.2.    "Tenant Work" as used in this Lease shall mean the
provision of the materials, components, labor and services encompassed within
the work described in the Tenant Design and Construction Process (as defined in
Exhibit "C"). Landlord shall provide a concession fund equal to Twenty-Eight
Dollars and Fifty Cents ($28.50) per rentable square foot ("Concession Fund").
The Concession Fund may be utilized to pay the cost of construction, demolition,
construction documentation and associated permits and fees, architectural and
engineering fees, moving expenses and other reasonable move-related expenses,
signage, Tenant's legal fees incurred in negotiations of this Lease, remaining
lease liability coverage and holdover penalties and furniture and equipment. The
Concession Fund shall be applied to the items described above in such amounts as
Tenant may determine, and disbursed by Landlord from time to time to Tenant, so
long as Tenant is not in default (which term for purposes of this Article 4.2



                                       5



shall not be deemed to be a circumstance entitled to the benefit of notice and
cure periods provided under Article 31 below) under this Lease, pursuant to the
Concession Fund Voucher Form attached hereto as Exhibit "D". Tenant covenants
that Tenant shall utilize a minimum of fifty percent (50%) of the Concession
Fund for direct hard cost improvements to the Premises. For purposes hereof, the
term "hard costs" shall mean all costs incurred by Tenant in the design,
engineering and construction of leasehold improvements in the Premises,
including all contractor and materialman charges. in no event shall Landlord
have any obligation to pay for costs relating to Tenant Work or for any of the
other items for which the Concession Fund may be utilized in an amount that
exceeds the Concession Fund. A reconciliation to establish that the requisite
portion of the Concession Fund has been expended for hard costs of improvements
to the Premises shall be submitted to Landlord by Tenant within sixty (60) days
after the completion of the Tenant Work. So long as Tenant has expended the
requisite portion of the Concession Fund on hard costs and Tenant is not in
default (which term for purposes of this Article 4.2 shall not be deemed to be a
circumstance entitled to the benefit of notice and cure periods provided under
Article 31 below) under this Lease, the portion of the Concession Fund not
disbursed to Tenant by the date of reconciliation referred to above shall be
credited against the Monthly Installments of Base Rent payable hereunder as
follows: (i) an amount up to $5.00 per rentable square foot shall be credited
against the next installments) of Base Rent payable hereunder and (ii) any
amount in excess of $5.00 per rentable square foot shall, after the credit
described in the immediately preceding clause has been exhausted, be credited in
twelve equal installments against the next twelve Monthly Installments of Base
Rent.

                   4.3.    Landlord and Tenant recognize and agree that floors
1, 7, 8 and 10 of the Centerpointe I Building constitute the Initial Space, that
the County of Fairfax ("County") has vacated the Initial Space and that Landlord
has made the Initial Space available to Tenant for Tenant Work on the date
hereof. Except for the 4th floor of the Centerpointe II Building, which shall be
used by the County for storage until February 28, 1993, Landlord shall make the
Subsequent Space available for possession by Tenant no later than December 31,
1992. If for any reason Landlord is unable to so deliver the Subsequent Space,
Landlord agrees to pay to Tenant, as Tenant's sole remedy for Landlord's
inability to deliver the Subsequent Space as aforesaid (as reimbursement for the
actual holdover penalty that Tenant will incur under its present lease for
premises located at 1525 Wilson Boulevard, Arlington, Virginia) (the "Wilson
Boulevard Lease"), an amount up to $75,000 per month, to be pro rated on a per
them basis if permitted under the Wilson Boulevard Lease (the "Holdover
Payment") and to the extent that such failure to deliver any segment of the
Subsequent Space causes Tenant to have less than 120 days to complete the Tenant
Work for any segment of the Subsequent Space, the Subsequent Rent Commencement
Date for such segment(s) of the Subsequent Space shall be extended by the number
of days needed to provide Tenant with 120 days to complete the Tenant Work.

         5.        Use of the Premises. Tenant shall not use or occupy, or
permit or suffer to be used or occupied, the Premises or any part thereof, other
than for the Permitted Use (set forth in Article 1.8), and except for any retail
uses that may be permitted on the first floor of the Centerpointe I Building
pursuant to Article 14.1.2 below.

         6.        Base Rent.



                                       6



                   6.1.1.  Covenant to Pay. Tenant covenants that it shall,
without any demand therefor and without set off or deduction whatsoever (except
as may be expressly permitted pursuant to Article 53.2 below), pay to Landlord
at Landlord's Address (set forth in Article 1.9) or to such other person and at
such other place as Landlord may from time to time designate in writing, in
lawful money of the United States of America, rent at the annual rate of the
Base Rent. Base Rent shall be payable monthly in installments (each a "Monthly
Installment of Base Rent"), in advance on or before the first day of each and
every calendar month during the Term from and after the Rent Commencement Date,
as to the Initial Space, and from and after the applicable Subsequent Rent
Commencement Date, as to each applicable segment of the respective Subsequent
Space.

                   6.1.2.  Advance Deposit of Base Rent. At the time of
execution of this Lease Tenant shall pay to Landlord an amount equal to the
first Monthly Installment of Base Rent for the Initial Space, to be applied by
Landlord on the Rent Commencement Date.

                   6.2.    Partial Month. If the Rent Commencement Date or a
Subsequent Rent Commencement Date is other than the first day of a month, Rent
(defined in Article 50.12), including, without limitation, Base Rent, due from
such date until the first day of the following month shall be prorated and shall
be payable on the Rent Commencement Date or the Subsequent Rent Commencement
Date, as applicable.

                   6.3.    Escalation of Base Rent. Commencing on May 1, 1994
("Escalation Date"), and on the first day of each May during the Term thereafter
(each a "Subsequent Escalation Date") (each such period from and after the
Escalation Date to the date which is one day prior to the next Subsequent
Escalation Date being herein defined as an "Escalation Period"), Base Rent per
rentable square foot shall be increased for each Escalation Period by an amount
equal to Two and Twenty-Five One Hundredths percent (2.25%) multiplied by the
difference between (i) Base Rent per rentable square foot, at the rate effective
on the day before the applicable Subsequent Escalation Date and (ii) the sum of
the Base Year Operating Expenses and the Base Year Real Estate Taxes per
rentable square foot. In addition to the foregoing escalation of Base Rent, the
Base Rent then in effect shall be increased by One Dollar ($1.00) per rentable
square foot at the beginning of the sixth (6th) Lease Year and by Two Dollars
($2.00) per rentable square foot at the beginning of the eleventh (11th) Lease
Year. By way of illustration of the foregoing formula, if the sum of Base Year
Operating Expenses and Base Year Real Estate Taxes per rentable square foot is
Five Dollars ($5.00), then on the Escalation Date Base Rent per rentable square
foot will increase to $13.90 per rentable square foot from and after the
Escalation Date until the next Subsequent Escalation Date.

                   6.4.    Independent Covenant; Survival. Tenant's covenant to
pay the Base Rent is independent of any other covenant, agreement, term or
condition of this Lease (subject to Article 53.2 below). Without limitation on
other obligations of Tenant which shall survive the expiration of the Term, the
obligation of Tenant to pay Base Rent shall survive the expiration of the Term.

         7.        Additional Rent.


                                       7



                   7.1.    Covenant to Pay. In addition to paying Base Rent,
Tenant covenants that it shall without (except as may be otherwise expressly
provided herein) any demand therefor and without set-off or deduction whatsoever
(subject to Article 53.2 below), pay to Landlord at Landlord's Address or to
such other person and at such other place as Landlord may from time to time
designate in writing, in lawful money of the United States of America, within
thirty (30) days of a statement of the amount due therefor (except as provided
in Article 7.5 with respect to estimated payments of Additional Rent and except
that if a different period for payment is specifically set forth, said different
period shall control) the following in this Article 7 (collectively, "Additional
Rent"):

                   7.1.1.  Real Estate Taxes. "Net Real Estate Taxes", as
defined below.

                           (a)       Tenant's Centerpointe I Proportionate Share
(as defined in Article 50.16 below) of Real Estate Taxes (as defined in Article
50.11) for the Centerpointe I Building in excess of Tenant's Centerpointe I
Proportionate Share of Base Year Real Estate Taxes for the Centerpointe I
Building ("Centerpointe I Net Real Estate Taxes").

                           (b)       Tenant's Centerpointe II Proportionate
Share (as defined in Article 50.16) of Real Estate Taxes for the Centerpointe II
Building in excess of Tenant's Centerpointe II Proportionate Share of Base Year
Real Estate Taxes for the Centerpointe II Building ("Centerpointe II Net Real
Estate Taxes").

                           (c)       Tenant's Centerpointe I Net Real Estate
Taxes and Tenant's Centerpointe II Net Real Estate Taxes are herein defined as
"Net Real Estate Taxes".

                           (d)       Upon the written request of Tenant, during
any year of the Term of this Lease, Landlord shall deliver a copy of the real
property tax assessment for the Buildings for that year and shall inform Tenant
whether or not Landlord intends to institute an appeal ("Tax Appeal") of the
real property tax assessment for either or ' both of the Buildings. If,
notwithstanding Landlord's intention not to appeal the real property tax
assessment in a particular year, Tenant in its reasonable judgment determines
that a Tax Appeal should be filed, then Tenant shall deliver written notice of
such determination to Landlord no later than the earlier of (i) thirty (30) days
following Landlord's delivery of Landlord's notice of its decision not to file a
Tax Appeal, or (ii) thirty (30) days prior to the deadline for filing the Tax
Appeal. In such event, Landlord, with counsel designated by Landlord, shall file
and prosecute a Tax Appeal with the same diligence as if Landlord had itself
made the determination to undertake such Tax Appeal, and Tenant may participate
and consult with Landlord in such proceedings. The cost and expense of any Tax
Appeal shall be an Annual Operating Cost, as defined in Article 7.4.1 below. In
the event Landlord receives a rebate or refund of any Real Estate Taxes with
respect to which Tenant has contributed its Proportionate Share hereunder,
Landlord shall deliver to Tenant its Proportionate Share of the rebate or
refund, up to an amount which is equal to the sum of the Net Real Estate Taxes
which may have been paid by Tenant in that year, within thirty (30) days after
the receipt thereof by Landlord.

                           (e)       For the Lease Year commencing January 1,
1996 the parties shall adjust Base Year Real Estate Taxes if the average of the
assessments for the Buildings (as opposed



                                       8



to changes in the tax rate or the percentage of the assessment upon which the
rate is based) for calendar years 1993, 1994 and 1995 ("Three Year Average
Assessment") deviates from the 1993 Base Year assessment ("Base Year
Assessment") by more than 5%. If the Three Year Average Assessment is not 5%
higher or 5% lower than the Base Year Assessment, Base Year Real Estate Taxes
shall continue to be 1993 calendar year Real Estate Taxes by the tax rate
effective in calendar year 1993. There shall be no readjustment of Tenant's
Proportionate Share of Real Estate Taxes for Lease Years 1993, 1994 or 1995. If
Base Year Real Estate Taxes are adjusted pursuant to this Article 7.1.1(e), the
escalations to Base Rent made pursuant to Article 6.3 shall be recalculated on
the basis of the adjusted Base Year Real Estate Taxes, and any underpayment or
overpayment of the Base Rent made prior to the adjustment of Base Year Real
Estate Taxes on the basis of the 1993 Base Year Real Estate Taxes during any
Escalation Period shall be paid by Tenant to Landlord, or by Landlord to Tenant,
within thirty (30) days of such recalculation.

                   7.1.2.  Lease Taxes. All Lease Taxes (defined in Article
50.7), unless Tenant shall be prohibited by law from paying the same, in which
event Landlord shall be entitled, at its election, to terminate this Lease by
written notice to Tenant, and Landlord and Tenant shall enter into a new lease
which will provide Landlord with economic benefits of an economic value as
closely as is equitably possible to the economic benefits that Landlord would
have enjoyed had Tenant been lawfully permitted to pay such Lease Taxes.

                   7.1.3.  Tenant Electricity. From and after the date on which
Tenant commences the conduct of its business therein for the Permitted Use, as
to the Initial Space, and as to any Subsequent Space, Tenant shall pay to
Landlord as Additional Rent, within thirty (30) days after receipt from Landlord
of each statement of the amount due, Landlord's actual cost in each period
chosen by Landlord, of supplying such quantity of electricity ("Tenant
Electricity") as is consumed by Tenant in the Premises ("Tenant Electricity
Costs"). Tenant Electricity shall include the electricity supplied to the common
areas of the interior portion (excluding the garage) of the Centerpointe I
Building (including, without limitation, the cost for taxes, fuel adjustment
charges, transfer charges and other like charges regularly passed on to the
consumer by the public utility furnishing electricity to the Buildings). Tenant
Electricity Costs shall be determined by Landlord (i) on the basis of a submeter
installed by Landlord, at Landlord's expense on the first floor of the
Centerpointe I Building and (ii) on the basis of a separate submeter for the
third, fourth and, if and when leased by Tenant pursuant to the first offer
rights described in Article 61 and the expansion rights described in Article 62,
on any other full floors of the Centerpointe II Building, all such meters to be
installed by Landlord at Landlord's expense. For any floor less than a full
floor in the Centerpointe II Building, Tenant Electricity Costs applicable to
such floor shall be determined by deeming Tenant's obligation to be equal to
that fractional share of Tenant Electricity Costs, the numerator of which is the
Rentable Area of the Premises on that floor and the denominator of which is the
Rentable Area of all leased premises on such floor of the Centerpointe II
Building which share a common electrical submeter and which were occupied during
the period in question, with equitable adjustments being made for occupancy
during only portions of such period. The calculation of the billing in said
statement shall be determined by Landlord in good faith, using reasonable
accounting principles, it being understood that Landlord shall not derive any
profit from the supplying of electricity. Landlord shall pass on to Tenant the
benefit of any bulk or



                                       9



discount rates for electricity that Landlord is able to obtain for the Buildings
and Landlord agrees to use its best efforts to obtain such reduced rates.

                   7.1.4.  Other Sums.  All other sums payable under this Lease
for any purpose, whether or not they are expressly designated as "Additional
Rent" or rent or would otherwise be considered rent, are herein payable as
"Additional Rent".

                   7.2.    Independent Covenant: Survival.  Tenant's covenant to
pay the Additional Rent is independent of any other covenant, agreement, term or
condition of this Lease (subject to Article 53.2 below). Without limitation on
other obligations of Tenant which shall survive the expiration of the Term, the
obligation of Tenant to pay Additional Rent shall survive the expiration of the
Term.

                   7.3.    Partial Year.  If the Rent Commencement Date is not
the first day of a calendar year or if the expiration date of the Term is not
the last day of a calendar year, the amount computed as Additional Rent with
respect to such partial calendar year under this Article 7 shall be prorated in
proportion to the portion of such calendar year falling within the Term.

                   7.4.    Operating Costs.  Tenant shall also pay as
"Additional Rent", "Net Annual Operating Costs", as defined below.

                           (a)       Tenant's Centerpointe I Proportionate Share
of Annual Operating Costs for the Centerpointe I Building in excess of Tenant's
Centerpointe I Proportionate Share of Base Year Operating Costs for the
Centerpointe I Building ("Centerpointe I Net Annual Operating Costs");

                           (b)       Tenant's Centerpointe II Proportionate
Share of Annual Operating Costs for the Centerpointe II Building in excess of
Tenant's Centerpointe II Proportionate Share of Base Year Operating Costs for
the Centerpointe II Building ("Centerpointe II Net Annual Operating Costs");

                           (c)       Tenant's Centerpointe I Net Annual
operating Costs and Tenant's Centerpointe II Net Annual Operating Costs are
together defined as "Net Annual Operating Costs".

         7.4.1.    The term "Annual Operating Costs" shall mean the direct
actual costs to Landlord, determined consistently on a cash, accrual or modified
accrual basis, at Landlord's option, of operating and maintaining the Property
during each calendar year of the Term. Consistent with the operation of a first
class office building in the Northern Virginia area, Landlord agrees to use its
reasonable efforts to minimize Annual Operating Costs to the same extent as if
the entire burden thereof were an unreimbursable obligation of Landlord. Such
'costs shall include, by way of example rather than of limitation, (A) charges
for, and taxes on, the furnishing to the Property of water and sewer service,
electric energy to common areas (other than interior common areas of the
Centerpointe I Building, the payment of which is governed by Article 7.1.3
above) and, if the building systems should be converted to receive the same,
steam or fuel and other utility services; (B) costs of elevator service,
maintenance of the Property, janitorial service and trash removal; (C)



                                       10



charges for governmental permits; (D) wages, salaries and benefits of employees
of Landlord, or of any management company, who are directly involved in
management of the Property (which costs shall be equitably allocated among the
buildings serviced by such employee), and management fees, overhead and
expenses; (E) premiums for hazard, rent, liability, worker's compensation and
other insurance; (F) costs arising under service contracts; (G) legal, auditing
and other professional and consulting fees; (H) repairs, replacements and
improvements which are in Landlord's reasonable judgment necessary to cause the
Buildings to comply with changes in existing law arising from and after the date
hereof or those which reduce or are expected or intended to result in a net
reduction (taking into account the cost of such improvement) in Annual Operating
Costs, in which case the cost thereof shall be included in Annual Operating
Costs as set forth in Article 7.4.3 below; (I) taxes, including the Fairfax
County BPOL gross receipts and gross expenditures taxes (other than Real Estate
Taxes and state and federal income taxes and any other income, profit,
franchise, capital stock, excise, estate, gift, succession, transfer or
recordation tax or levy); (J) charges, if any, for the Buildings' share of the
costs of (i) any common means of vehicular access and loading facilities and
(ii) common facilities which the Buildings may share with others, (K) the cost
of all other items which under standard accounting practices constitute
operating or maintenance costs which are reasonably allocable to the Property or
any portion thereof.



                                       11



                   7.4.2.  The term "Annual Operating Costs" shall not include:
(A) depreciation; (B) principal and interest on encumbrances; (C) ground rents;
(D) costs actually reimbursed through insurance proceeds to repair or replace
damage by fire or insured other casualty; (E) compensation and benefits of
executive officers of Landlord (or its managing agent above the level of
building manager; (F) Electricity Costs)(defined in 1,101--Article 7.1.4); (G)
commissions payable to leasing brokers and advertising costs and other
marketing expenses associated with procuring new tenants; (H) expenditures for
capital improvements except those referred to in Section 7.4.1(H); (I) costs
actually reimbursed by condemnation awards or under contractor warranties; (J)
costs of preparing tenant space for other tenants; (K) legal fees relating to
preparation of tenant leases, financing of the Buildings and violations by the
Landlord or any tenant under tenant leases; (L) fees or charges paid to any
Affiliate of Landlord to the extent such fees or charges exceed the fees or
charges that would have been incurred to an independent entity in an arm's
length transaction; (M) cost of utilities and services furnished to retail
tenants who pay directly for such utilities and services under their leases;
(N) costs of original artwork; (0) costs of furnishing any additional or
special service to any tenant, if such service is not also available to Tenant
at no charge; (P) costs of upgrading the common areas of the Buildings beyond
the level of maintenance, repair, modification and replacement necessary to
preserve the first class standard of quality prevailing in such areas on the
date of this Lease; (Q) the cost of any fine for Landlord's failure to comply
with any laws for which this Lease imposes the obligation on Landlord to
comply, (R) the wages and benefits of any personnel employed to manage the
garage; (S) the cost of any personnel, materials or services shared by the
Buildings and any other buildings owned or operated by Landlord, to the extent
reasonably allocable to such other buildings; (T) annual increases in rent for
the space occupied by the management office in a Building in excess of annual
increases in the Consumer Price Index (CPI-W), DC-MD-VA; and (U) phase outs of
chlorofluorocarbon refrigerants which do, not result in a net decrease in
Annual Operating-Costs.

                   7.4.3.  If there shall be purchased any item of capital
equipment or made any capital expenditure required by changes in existing law or
designed to result in net savings or reductions in Annual Operating Costs
(including any phase outs of chlorofluorocarbon refrigerants which result in a
net decrease in Annual Operating Costs) incurred or expected to be incurred or
in Electricity Costs applicable to the Buildings generally, then the costs for
same shall be included in Annual Operating Costs for the calendar year in which
the costs are incurred and subsequent calendar years, on a straight line basis,
to the extent that such items are amortized over their useful life, as
determined pursuant to Generally Accepted Accounting Principles, with an
interest factor equal to the Landlord's actual cost of funds. If there shall be
leased any capital equipment to meet requirements of the law or designed to
result in savings or reductions in Annual Operating Costs, or in Electricity
Costs applicable to the Buildings generally, then the rental and other costs
paid for such leasing shall be included in Annual Operating Costs for the
calendar years in which they were incurred, but only to the extent that the
amortized cost of such items could have been included hereunder had they been
purchased.

                   7.4.4.  In determining Annual Operating Costs for any year,
including Base Year Operating Expenses, if for thirty (30) or more consecutive
days less than 100% of the Rentable Area of the Centerpointe I Building or the
Centerpointe II Building shall have been occupied by tenants, or if any tenant
is separately obtaining janitorial services or any other services being


                                       12



furnished by Landlord hereunder, then Annual Operating Costs shall be deemed for
such year to be an amount equal to the like expenses that would normally be
expected to be incurred had such occupancy of the Centerpointe I Building and
the Centerpointe II Building been at least 100% throughout such year, and had
Landlord been furnishing all customary services to tenants, as reasonably
determined by Landlord. In making the adjustment called for under this Article
7.4.4, Landlord shall not adjust any element of Annual Operating Costs which
would not vary with the occupancy rate of the Buildings. This Article 7.4.4
shall not be applied in a manner which would enable Landlord to recover from the
tenants in either Building any amount in excess of the costs actually incurred
by Landlord that are attributable to the occupied premises in such Building.

                   7.4.5.  If, at any time during the Term of this Lease Tenant
shall vacate all or any portion of the Premises (and such portion of the
Premises shall not be occupied by any assignees or sublessees of Tenant), then,
to the extent that Landlord is able to suspend janitorial services for such
portion of the Premises vacated by Tenant and receive a reduction of the amounts
owing under Landlord's janitorial contract, Landlord shall credit against
Tenant's Base Rent obligation under this Lease the amount by which Landlord is
able to reduce its janitorial costs with respect to the vacant space (but not by
more than the janitorial costs incurred with respect to such space in the Base
Year).

                   7.5.    Payment of Estimated Additional Rent.  Anything
contained in this Lease to the contrary notwithstanding, Landlord shall be
entitled, at its discretion, to make reasonable estimates, prior to April 30 of
each calendar year, of the amounts of Additional Rent to become due for Net
Annual operating Costs and Net Real Estate Taxes for any full or partial
calendar year under this Article, and to require Tenant to pay, (i) in the case
of Net Annual Operating Costs, such estimated amounts in equal monthly
installments on the first day of each month during each calendar year, and (ii)
in the case of Net Real Estate Taxes, such estimated amounts in equal monthly
installments on the first day of each month during a 12-month period ending not
more than 60 days before the last day in each calendar year when any annual Real
Estate Tax may be paid without interest or penalty; provided, however, that
whenever an estimate of Additional Rent shall be revised as aforesaid, Landlord
shall have the right to increase the monthly installments to be paid thereafter
for that category so that such installments, when added to the installments
which Tenant was theretofore required to pay for the same category, shall equal
the increased estimate. Landlord's estimate of Annual Operating Costs for the
upcoming calendar year shall not exceed the Annual Operating Costs incurred
during the preceding calendar year by more than ten percent (10%). After the end
of each calendar year (for Net Annual Operating Costs) or the end of the
applicable 12-month period (for Net Real Estate Taxes), Landlord shall cause the
actual amount of such Additional Rent to be computed and statements thereof to
be sent to Tenant; and Tenant shall, within 30 days after any statement is sent
to Tenant, pay to Landlord the amount of any deficiency shown therein. If such
statement shall show that Tenant has made an overpayment, Tenant shall receive a
credit to the extent of such overpayment, which credit shall be made against the
installment of Base Rent next falling due hereunder, or refunded to Tenant if
occurring at the end of the Term, and Landlord's obligation to fund such a
refund shall survive the expiration of the Term of this Lease.



                                       13



                   7.6.    Disputes.  Unless Tenant, within 180 days after
Landlord shall deliver to Tenant Landlord's computation of Base Year Operating
Expenses and Base Year Real Estate Taxes, or any other statement of Additional
Rent, shall give notice to Landlord that Tenant disputes said statement,
specifying in detail the basis for such dispute, each statement furnished to
Tenant by Landlord under any provision of this Article shall be conclusively
binding upon Landlord and Tenant as to the particular Additional Rent due from
Tenant for the period represented thereby. Pending resolution of any dispute,
Tenant shall pay the Additional Rent in accordance with the statements furnished
by Landlord. Notwithstanding the foregoing, if Tenant in any year shall timely
elect to cause an audit to be performed of Landlord's statement, and the audit
reveals, in Tenant's reasonable judgment, that a component of the Annual
Operating Costs may have been incorrectly charged in the past, Tenant shall have
the right to review Landlord's books as to that item only, for the three
calendar years prior to the year in which the audit is performed and any
discrepancies shall be adjusted, and any reimbursement of the cost of the audit,
shall occur as provided below (except that the standard of a 5% discrepancy
giving rise to an obligation on the part of Landlord to reimburse Tenant's audit
costs shall relate to the components of Operating Costs that Tenant was entitled
to audit for such prior years, rather than to Operating Costs in the aggregate).
Landlord agrees, upon prior written request, to make Landlord's books and
records which are relevant to any operating statement available at Landlord's or
its agent's offices during normal business hours for inspection by Tenant and by
a "Big Six" accounting firm (or other national or regional accounting firm to be
approved by Landlord, which approval shall not be unreasonably withheld or
delayed) representing Tenant at Tenant's sole expense (unless Tenant's
inspection or audit discloses a discrepancy of more than five percent (5%) in
the Annual Operating Costs, 'in which event the audit or inspection shall be at
Landlord's expense), provided that any disputed amounts shall have been paid by
Tenant to Landlord. Any discrepancy disclosed by the inspection or audit by
Tenant's "Big Six" accounting firm (or other national or regional accounting
firm approved by Landlord as aforesaid) shall be corrected by payment of any
shortfall to Landlord by Tenant within thirty (30) days after the discrepancy is
revealed, or by a credit against the next payment(s) of Base Rent or Additional
Rent hereunder.

         8.        Late Charge; Interest. If any payment or any part thereof to
be made by Tenant to Landlord pursuant to the terms of this Lease shall become
overdue for a period in excess of five (5) calendar days, a "Late Charge" of
$.03 for each dollar so overdue shall be paid by Tenant for the purpose of
defraying the expense incident to handling such delinquent payment, together
with interest from the date when such payment or such part thereof was due, at
the Lease Interest Rate (defined in Article 50.6). The foregoing "Late Charge"
(but not interest at the Lease Interest Rate) shall not be payable, however, for
the first two (2) infractions during any twelve (12) month period. Nothing
herein shall be construed as waiving any rights of Landlord arising out of any
default of Tenant, by reason of Landlord's imposing or accepting any such Late
Charge or interest; the right to collect the Late Charge and interest is
separate and apart from any rights relating to remedies of Landlord after
default by Tenant including, without limitation, the rights of Landlord pursuant
to Article 31 of this Lease.

         9.        Services.



                                       14


                   9.1.    Landlord agrees that when Tenant occupies the Initial
Space and the Subsequent Space for the Permitted Use, it shall provide or cause
to be provided the following:

                   9.1.1.  HVAC.  In accordance with standards appropriate for a
first-class office building attached hereto as Exhibit "G", furnish heat,
ventilation and air-conditioning to the Premises during ordinary Business Hours
(defined in Article 50.8) by a "Variable Air Volume System", subject to the
following: (A) Heating and/or air-conditioning supplied to Tenant during times
other than Ordinary Business Hours ("HVAC Off-Hours") required by Tenant shall
be supplied on a floor-by-floor basis upon reasonable prior notice, and shall be
paid for by Tenant as Additional Rent within 30 days after Tenant's receipt of
each bill therefor, at the "HVAC Off-Hours Rate" (defined in Article 50.4); (B)
Landlord shall not be responsible for the failure of the heating or
air-conditioning system to meet the aforesaid standards if such failure results
from occupancy of the Premises by more than an average of one person for each
100 square feet of usable space or if Tenant uses equipment and the combined
electrical load of Tenant's equipment exceeds 4.0 watts, 120 volts per square
foot of floor area in any one room or area; (C) In addition, if the Premises are
used in a manner exceeding the aforementioned occupancy or electric load
criteria, Tenant shall pay to Landlord as Additional Rent, within 30 days after
Tenant's receipt of each bill therefor, Landlord's costs of supplying heating or
air conditioning resulting from such excess, at such rates as Landlord shall
establish therefor; (D) If, due to the use of the Premises in a manner exceeding
the aforementioned occupancy or electrical load criteria or if Tenant has
requested and installed a supplemental HVAC system, or due to the arrangement of
partitioning or the distribution system within the Premises, impairment of
normal operation of the heating or air-conditioning in the Premises results,
necessitating changes in the heating or air-conditioning distribution system
within the Premises, such changes may be made by Landlord upon request by
Tenant, subject to the provisions of Article 9.2 of this Article 9; Tenant shall
pay to Landlord as Additional Rent the cost of any such change within 30 days
after Tenant's receipt of a bill therefor; (E) Tenant agrees at all times to
cooperate fully with Landlord and to abide by all necessary regulations and
requirements which Landlord may prescribe for the proper functioning and
protection of the heating and/or air-conditioning system; (F) The foregoing
heating and air-conditioning services shall be subject to any statute,
ordinance, rule, regulation or resolution for energy conservation which may be
promulgated by any governmental agency or organization and which Landlord shall,
in Landlord's reasonable opinion, be by law required to abide by.

                   9.1.2.  Elevators.  Provide passenger elevator service to the
Premises during ordinary Business Hours, with two elevators in each Building
subject to call at all other times. Provide freight elevator service to the
Premises subject to reasonable scheduling by Landlord.

                   9.1.3.  Access.  Furnish to Tenant's employees and agents
access to the Premises (including the fire stairs for transportation between
floors of the Premises, subject to any code requirements) and garage at all
times, subject to compliance with such reasonable security measures as shall be
from time to time in effect for the Buildings. In addition, Tenant shall have
such access to the roof of the Buildings as will be necessary for Tenant to
construct and maintain the alterations as described in Article 15.2 below.
Tenant may use (i) the kitchen exhaust shaft in the Centerpointe I Building for
data and telecommunications wiring, unless Landlord elects to



                                       15



terminate such right in order to increase the fresh air capacity in the
Centerpointe I Building, and (ii) the existing auxiliary cooling towers on the
roof of the Centerpointe I Building.

                   9.1.4.  Janitorial.  Provide to the Premises janitorial
service in accordance with the schedule annexed hereto as Exhibit "E". Any and
all additional or specialized janitorial service desired by Tenant shall be
contracted for by Tenant directly and the cost and payment thereof shall be the
sole responsibility of Tenant.

                   9.1.5.  Water.  Provide hot and cold water, and lavatory and
toilet fixtures at the Buildings' core, and water fountains, on each floor.

                   9.1.6.  Public Areas.  Keep and maintain the public areas of
the Buildings clean and in good working order, and the sidewalks adjoining the
Buildings clean and in good repair and substantially free from accumulations of
snow and ice.

                   9.1.7.  Repairs.  Make all structural repairs to the
Buildings, all repairs which may be needed to the mechanical, HVAC, electrical
and plumbing systems in and servicing the Premises, and all repairs to exterior
or atrium windows and glass (including caulking and weather-stripping) and all
repairs to the common and public areas and facilities of the Buildings and the
Property (including those portions of the Centerpointe I Building that would be
common or public areas if such Building was a multi-tenant Building).

                   9.1.8.  Electricity.  Furnish electric energy as required by
Tenant for general light and power use in the Premises, in addition to the
electric energy required by Tenant for distribution of the Buildings' heating,
ventilation and air-conditioning systems to the Premises, all subject to the
following:

                           (a)       With respect to light fixtures standard in
the Buildings, Landlord shall furnish and install all replacement fluorescent
tubes, starters, lamps and ballasts required in the Premises, with the expense
thereof to be included in Annual Operating Costs.

                           (b)       Tenant's use of electric energy in the
Premises shall not at any time exceed the capacity of any of the electrical
conductors and equipment in or serving the Premises. In the event that Tenant
shall require electric energy for use in the Premises (exclusive of such
electric energy as is required for distribution of the heating, ventilating and
air-conditioning systems to the Premises) in excess of 4.0 watts per square foot
as hereinabove provided, and if, in Landlord's reasonable judgment, Landlord's
facilities are inadequate for such additional requirements and if electric
energy for such additional requirements is available to Landlord, Landlord, upon
written request and at the cost and expense of Tenant, will furnish and install
such additional wires, risers, conduits, feeders, switchboards and circuit
panels as reasonably may be required to supply such additional requirements of
Tenant, provided (x) that the same shall be permitted by applicable laws and
insurance regulations, (y) that, in Landlord's reasonable judgment, the same are
necessary and will not cause damage or injury to the Buildings or the Premises
or cause or create a dangerous or hazardous condition or entail excessive or
unreasonable alterations or repairs or interfere with or disturb other tenants
or occupants and (z) that Tenant, at Tenant's expense, shall, concurrently with
the making of such written request, execute and deliver


                                       16



to Landlord Tenant's written undertaking, in form and substance reasonably
satisfactory to Landlord, obligating Tenant to fully and promptly pay the entire
cost and expense of so furnishing and installing any such additional wires,
risers, conduits, feeders, switchboards, and/or circuit panels, subject to
Article 9.2 of this Article 9.

                   9.2.    Tenant shall not install any equipment of any kind
whatsoever which might necessitate any changes, replacements or additions to any
of the heating, ventilating, air-conditioning, electric, sanitary, elevator or
other systems serving the Premises or any other portion of the Buildings, or to
any of the services required of Landlord under this Lease, without the prior
written consent of Landlord, which shall not be unreasonably withheld so long as
there is no adverse impact on any other tenant of a Building and there is no
other adverse impact on the structural integrity of the Buildings, and in the
event such consent is granted, such replacements, changes or additions shall be
paid for by Tenant at Tenant's sole and exclusive expense. At the expiration or
earlier termination of the Term, Tenant shall pay Landlord's cost of restoring
such systems to their condition prior to such replacements, changes or additions
if at the time that Landlord granted its consent to the replacements, changes or
additions, Landlord conditioned its consent to their removal at the end of the
Term or earlier termination of this Lease. Landlord agrees not to unreasonably
require the removal of systems that are customarily installed in office
buildings.

                   9.3.    In case of accident, strikes, inability to obtain
supplies, breakdowns, repairs, renewals or improvements to the Buildings or
replacement of machinery therein, or for other cause deemed sufficient by
Landlord in its good faith judgment, the operation of the elevators or other
machinery or apparatus may be changed or suspended. As to heat, ventilation,
air-conditioning, cleaning, electricity, elevator, access, janitorial, water,
repairs and any other services provided to the Premises or Buildings, Landlord
shall not be responsible or liable in any way for any failure, defect in supply
or character of, interruption or inadequacy in the quantity or quality of the
same where caused by war, civil commotion, governmental restrictions or
regulations, strikes, labor disturbances, inability to obtain adequate supplies
or materials, casualties, repairs, replacements, or act or omission or
requirement of the public utility serving the Buildings, or any other cause
beyond Landlord's reasonable control whether similar or dissimilar to the
foregoing. Notwithstanding the foregoing, if any interruption of utilities or
services shall continue for more than five (5) consecutive business days and
shall render any portion of the Premises unusable for the normal conduct of
Tenant's business, and if Tenant in fact ceases to use and occupy such portion
of the Premises for the normal conduct of its business because of its inability
due to the interruption (other than, e.g., entry to retrieve files and other
materials), then all Rent payable hereunder with respect to such portion of the
Premises shall be abated retroactively to the first (1st) day of such
interruption and continuing until full use of such portion of the Premises is
restored to Tenant.

                   9.4.    Any service which Landlord is required to furnish
hereunder may, at Landlord's option, be furnished from time to time in whole or
in part by employees of Landlord, by Landlord's managing agent or by others.


                                       17



                   9.5.    Tenant understands that persons selected by Landlord
to provide services which Tenant is entitled to (or elects to) receive may be
allowed by Landlord to perform these or other services at the Centerpointe II
Building for other tenants at the direct cost and expense of tenants. Tenant
acknowledges that such persons are independent contractors and not agents or
instrumentalities of Landlord and that such arrangements as Tenant may enter
into with such persons are independent of this Lease. Landlord's engagement of
any such independent contractors shall not diminish or impair Landlord's
obligation to provide the services and the level of services required by this
Lease.

                   9.6.    Landlord and Tenant acknowledge that janitorial
services for the Buildings shall initially be furnished by Red Coat, Inc.
Landlord shall not employ any other cleaning contractor for the Centerpointe I
Building without Tenant's prior written approval, which shall not be
unreasonably withheld, conditioned or delayed. In the event Tenant determines
that the janitorial services being furnished by Landlord pursuant to Article
9.1.4 above are unsatisfactory, in Tenant's reasonable judgment, Tenant shall
deliver written notice to Landlord specifying in detail the manner in which the
services are deemed deficient. If the deficiencies are not, in Tenant's
reasonable judgment, substantially corrected during the next succeeding sixty
(60) days, then Tenant may deliver a further notice to Landlord advising
Landlord of such fact and Landlord shall either terminate the contract for
janitorial services to the Buildings or submit the matter to arbitration in
accordance with Article 65 below. If the arbitrator decides in favor of Tenant,
Landlord shall terminate the contract for janitorial services to the Buildings.
Promptly thereafter, Landlord shall enter into a new contract for janitorial
services to the Buildings with a contractor approved by Tenant, such approval
not to be unreasonably withheld, conditioned or delayed. If the arbitrator
decides in favor of Landlord, Tenant shall be barred from sending the notice
permitted by this Article 9.6 for a one year period following such
determination.

                   9.7.    Landlord and Tenant acknowledge that the Buildings
shall initially be managed by LPC Commercial Services, Inc. Landlord agrees that
the term of any management agreement for the Buildings shall not exceed two (2)
years, shall be terminable with cause upon sixty (60) days' prior written notice
and that the fee payable to any manager under each contract shall be at the
then-prevailing market rate for first class buildings comparable to the
Buildings in the Northern Virginia area. In the event Tenant determines that the
manager of the Buildings is not operating the Buildings in a first class manner,
in Tenant's reasonable judgment, then Tenant may deliver written notice to
Landlord specifying in detail the manner in which the operation of the Buildings
is deemed deficient. If the deficiencies are not, in Tenant's reasonable
judgment, substantially corrected during the next succeeding sixty (60) days,
then Tenant may deliver a further notice to Landlord advising Landlord of such
fact and Landlord shall either terminate the contract for management services to
the Buildings or submit the matter to arbitration in accordance with Article 65
below. If the arbitrator decides in favor of Tenant, Landlord shall terminate
the management contract for the Buildings. Promptly thereafter, Landlord shall
enter into a new contract for management services to the Buildings with a
managing agent approved by Tenant, such approval not to be unreasonably
withheld, conditioned or delayed. If the arbitrator decides in favor of
Landlord, Tenant shall be barred from sending the notice permitted by this
Article 9.7 for a one year period following such determination.



                                       18



                   9.8.    In the event Tenant at any time after the Base Year
requests with specificity that Landlord adjust (either to increase or to
decrease) the level of services being furnished to the Centerpointe I Building,
Landlord agrees to confer with Tenant about such request and to make any
adjustment requested by Tenant that does not impair Landlord's operation and
maintenance of the Centerpointe I Building or adversely affect Base Year
Operating Expenses. Landlord agrees to consult with Tenant at Tenant's request
from time to time about the services being furnished hereunder to the
Centerpointe I Building, and not to adopt or materially modify an annual
operating budget for the Centerpointe I Building without first reviewing said
budget with Tenant.

         10.       Repairs and Condition of Premises. Tenant covenants that at
the expiration or other termination of this Lease, Tenant shall leave the
Premises, and during the Term will keep the same, in good order and condition,
ordinary wear and tear, damage by fire or other casualty alone excepted; and for
that purpose and except as stated, Tenant will make all necessary repairs and
replacements that are not the responsibility of Landlord under this Lease.
Tenant shall also at all times (subject to Article 9.1.4 hereof) remove all
dirt, rubbish, waste and refuse from the Premises and at the termination of the
Term will also have had removed all of Tenant's property therefrom, to the end
that Landlord may again have and repossess the entire Premises in good order and
condition. In the event that any repair is required by reason of such removal or
any negligence or abuse of Tenant or its agents or employees, Landlord may,
after providing Tenant with notice (except in cases of emergency) of Landlord's
intent to make such repair and Tenant's failure to make such repair within five
(5) days of receipt of such notice, make such repair and Tenant shall, upon
demand pay to Landlord as Additional Rent the cost actually and reasonably
incurred by Landlord thereof, together with interest thereon at the Lease
Interest Rate.

         11.       Compliance with Law. Tenant agrees to comply promptly with
all laws, ordinances, regulations and other requirements whatsoever, including
without limitation environmental laws, of any and all Federal, State, or local
authorities or of the Board of Fire Underwriters or any insurance organizations,
associations or companies, with respect to the Premises and any property owned
or leased by Tenant and located within the Premises, subject, however, to
Landlord's obligations under Article 9 above, this Article 11 and Article 52
below. Landlord and Tenant each agree that neither shall knowingly do or commit,
or suffer to be done or committed anywhere in the Buildings, any act or thing
contrary to any of the laws, ordinances, regulations and requirements
hereinabove referred to in this Article. Tenant shall give Landlord prompt
written notice of any accident in the Premises and of any breakage, defect or
failure in any of the systems or equipment servicing the Premises. Landlord
shall be responsible for any required compliance with legal requirements
relating to the condition of the base Buildings (not relating to tenants'
individual uses of their premises or any tenant work associated with their
premises). If a condition exists such that if Tenant were to complete the Tenant
Work as provided herein Tenant would be unable to obtain the required
certificate of occupancy (or nonresidential use permit, if applicable) so that
Tenant would be unable to lawfully occupy the Premises for the Permitted Use
because of any violation of a legal requirement relating to the condition of the
base Buildings as aforesaid, Tenant shall notify Landlord in writing of such
violation. Landlord shall use its best efforts to cure the defect and shall have
ninety (90) days to satisfy such legal requirement or to obtain the certificate
of occupancy (or non-residential use permit, if applicable) on behalf of Tenant.
There shall be an equitable abatement of Rent for portions of the Premises



                                       19



which Tenant would not lawfully be able to occupy equal to the length of the
period that Tenant is actually delayed in occupying that space. If Landlord has
not satisfied the legal requirement or otherwise obtained the certificate of
occupancy (or non-residential use permit, if applicable) for Tenant within such
ninety (90) days, Tenant shall have the right to terminate this Lease which
shall be Tenant's sole remedy under this Article 11.

         12.       Estoppel Certificate.

                   12.1.   Tenant shall from time to time, within fifteen (15)
days after Landlord's request or that of any mortgagee of Landlord, execute and
deliver to Landlord a written instrument certifying (i) that this Lease is in
full force and effect and has not been modified, supplemented or amended (or, if
there have been modifications, supplements or amendments, that it is in full
force and effect as modified, supplemented or amended, and stating such
modifications, supplements and amendments); (ii) the dates to which Base Rent
and Additional Rent and any other charges arising hereunder have been paid;
(iii) the amount of any prepaid rents or credits due Tenant, if any; (iv) if
applicable, that Tenant has accepted possession and has entered into occupancy
of the Premises, and certifying the Lease Commencement Date, each Subsequent
Lease Commencement Date, the Expansion Space Lease Commencement Date (as defined
in Article 62 below), the Rent Commencement Date, each Subsequent Rent
Commencement Date, the Expansion Space Rent Commencement Date (as defined in
Article 62 below) and the Termination Date; (v) whether or not, to the best
knowledge of the Tenant, all conditions under the Lease to be performed by
Landlord prior thereto have been satisfied and whether or not Landlord is then
in default in the performance of any covenant, agreement or condition contained
in this Lease and specifying each, if any, unsatisfied condition and each, if
any, default of which the signer may have knowledge; and (vi) any other fact or
condition reasonably requested. Any certification delivered pursuant to the
provisions of this Article shall be intended to be relied upon by Landlord or
any of its partners and any mortgagee or prospective mortgagee or purchaser of
the Property or of any interest therein.

                   12.2.   The failure of Tenant to execute, acknowledge and
deliver to Landlord a written instrument in accordance with the provisions of
this Article 12 within the fifteen (15) day period above provided shall
constitute an acknowledgment by Tenant, which may be relied upon by any
mortgagee or prospective mortgagee or any purchaser of either or both of the
Buildings or of any interest therein, that this Lease has not been modified,
supplemented or amended except as set forth in Landlord's request, and is in
full force and effect (or in full force and effect as so modified, supplemented
or amended), that the Base Rent, Additional Rent and any other charges arising
hereunder have not been paid beyond the respective due dates immediately
preceding the date of such request, that Tenant has no right of set-off or other
defense to this Lease and of the truth of such other facts and conditions as
shall have been requested to be certified, and shall constitute, as to any
person entitled to rely as aforesaid, a waiver of any defaults which may exist
prior to the date of such request. Notwithstanding the foregoing, Tenant's
failure to furnish such written instrument within five (5) days after Landlord's
second written request therefor, shall constitute a default under this Lease.



                                       20



                   12.3.   Landlord agrees, upon not less than fifteen (15)
days after receipt of Tenant's written request, to execute and deliver a written
instrument to Tenant containing the statements and certifications set forth in
Article 12.1, with appropriate changes reflecting the identity of the parties
with respect to clause (v) of Article 12.1. Such statement of Landlord shall not
be binding on a Senior Holder with respect to those matters set forth in Article
58 below and may be relied upon by Tenant and any assignee or subtenant of
Tenant.

                   12.4.   The failure of Landlord to execute and deliver to
Tenant a written instrument in accordance with the provisions of Article 12.3
within the fifteen (15) day period above provided shall constitute an
acknowledgment by Landlord, which may be relied upon by any prospective assignee
or subtenant of Tenant, that the Lease has not been modified, supplemented or
amended except as set forth in Tenant's request, and is in full force and effect
(or in full force and effect as so modified, supplemented or amended), that the
Base Rent, Additional Rent and any other charges arising hereunder have been
paid through the respective due dates immediately preceding the date of such
request, and of the truth of such other facts and conditions as shall have been
requested and certified, and shall constitute, as to any person entitled to rely
as aforesaid, a waiver of any defaults which may exist prior to the date of such
request. The provisions of this Article 12.4 shall not be binding upon any
Senior Holder with respect to those matters set forth in Article 58 below.

         13.       Rules and Regulations. Tenant agrees to observe the rules and
regulations for the Buildings attached hereto as Exhibit "F" and made a part
hereof and such additional reasonable rules and regulations and any
modifications thereto made from time to time by Landlord, which, in Landlord's
reasonable judgment, may be desirable for the use, entry, operation and
management of the Premises, the Property or the Buildings, each of which rules
and regulations and any additions and modifications thereto shall be deemed a
part of this Lease with the same effect as though written herein. Tenant
covenants that all such rules and regulations shall be faithfully observed and
complied with by Tenant, and to cause Tenant's agents, employees and invitees
and all those visiting the Premises or claiming under Tenant. Landlord agrees
not to apply the rules and regulations in a discriminatory manner as between
tenants of the Buildings.

         14.       Assignment and Subletting.

                   14.1.1. So long as Tenant is not in default under this
Lease, upon ten (10) days prior written notice to Landlord, Tenant shall have
the right at any time without Landlord's consent to sublet or otherwise permit
the occupancy of all or a portion of the Premises, or to assign this Lease to
any company or entity which is an Affiliate of Tenant or to any company or
entity which is wholly-owned by Tenant or to any company or entity which shall
acquire all of the stock or substantially all of the assets of Tenant. Any
sublessee or assignee permitted pursuant to this Article 14.1.1 without
Landlord's prior consent shall be bound by all restrictions on transfer under
this Article 14 generally.

                   14.1.2. Tenant shall not mortgage, pledge or encumber this
Lease, collaterally or otherwise. Except as provided in Section 14.1.1 above,
Tenant shall not assign this Lease, or sublet or underlet the Premises or any
part thereof, or permit any other person or entity to occupy



                                       21



the Premises or any part thereof, without on each occasion first obtaining the
written consent of Landlord, which consent shall not be unreasonably withheld,
conditioned or delayed by Landlord. Without limiting the foregoing, Tenant
acknowledges that it shall be reasonable for Landlord to withhold its consent if
such subtenant's or assignee's business is not suitable for a first-class office
building or would otherwise inhibit Landlord's marketing efforts or detract from
the value of the Buildings. Further, Landlord shall not unreasonably withhold or
delay its consent to a proposed sublease or subleases of portions of the first
floor of the Centerpointe I Building for retail uses which would constitute an
amenity to Tenant's employees, provided, however, any proposed retail sublease
must not conflict with the terms of any of the then-existing leases for the
Buildings, must be for an amount of space and type of use that complies with all
laws, including but not limited to zoning proffers for the Property, the
proposed use must be suitable for a first-class office building, and must not
otherwise inhibit Landlord's marketing efforts or detract from the value of the
Buildings and must otherwise be in form and substance reasonably satisfactory to
Landlord. In the event that Landlord should withhold its consent to a sublease
or assignment and Tenant should contest the reasonableness of Landlord's action,
the parties shall submit the matter to arbitration pursuant to Article 65 below.

                   14.2.   Except for subleases and assignments permitted
pursuant to Section 14.1.1, at least 20 days prior to any proposed subletting or
assignment, Tenant shall submit to Landlord a statement seeking Landlord's
consent and containing the name and address of the proposed subtenant or
assignee, the terms of the proposed sublease or assignment and such financial
and other information available to Tenant with respect to the proposed subtenant
or assignee as Landlord may reasonably request. Landlord shall indicate its
consent or non-consent within 14 days of its receipt of Tenant's submission. If
Landlord has not responded to Tenant within such 14 day period, Tenant shall
deliver a second notice to Landlord advising Landlord of the proposed assignment
or sublease and Landlord's failure to respond to the second notice within 4 days
of receipt thereof shall be deemed to be consent to the proposed sublease or
assignment. Should Landlord agree to an assignment or sublease, Tenant will pay
to Landlord on demand a sum equal to all of Landlord's reasonable costs,
including reasonable attorneys' fees, incurred in connection with such
assignment or transfer. Landlord shall furnish written reasons for any
non-consent.

                   14.3.   Tenant shall have 120 days from its receipt of
Landlord's consent as described in Article 14.2 of this Article 14 to enter into
the proposed sublease or assignment substantially in accordance with the terms
and with the identified subtenant or assignee described in Tenant's statement to
Landlord, and in accordance with such other terms required by this Lease, and
Tenant shall submit a fully executed sublease or assignment to Landlord.

                   14.4.   A subletting shall not convey to any subtenant the
right to exercise or receive any lease renewal option rights or space option
rights of the Premises, special privileges or extra services granted to Tenant
by this Lease, or addendum or amendment thereto or letter of agreement. Any
sale, assignment, mortgage or transfer of this Lease or sublease of the Premises
which does not comply with the provisions of this Article 14 shall be void.

                   14.5.   Except for subleases or assignments permitted by
Article 14.1.1, in the event that Tenant at any time desires to sublease or
assign all or part of its interest in the Premises


                                       22



or the Lease or any portion thereof which, when aggregated with all other
portions of the Premises then subject to subleases collectively comprises
greater than thirty-six percent (36%) of the Premises ("Proposed Recapture
Space"), then Tenant shall deliver a notice to Landlord ("Recapture Notice")
advising Landlord of such fact and specifying in good faith the date as of which
Tenant desires the assignment or sublease to take effect (the "Proposed Transfer
Date"). Tenant may deliver the Recapture Notice prior to identifying a
prospective assignee of this Lease or sublessee of the Proposed Recapture Space.
Landlord shall have the right in its absolute discretion to terminate this Lease
as to the Proposed Recapture Space. Landlord may exercise such right to
terminate by giving written notice to Tenant within twenty-one (21) days after
receipt of the Recapture Notice. If the Proposed Recapture Space does not
constitute the entire Premises and Landlord elects to terminate this Lease with
' respect to the Proposed Recapture Space, then (a) Tenant shall tender the
Proposed Recapture Space to Landlord on the Proposed Transfer Date as if such
specified date had been originally set forth in this Lease as the expiration
date of the Term with respect to the Proposed Recapture Space, and (b) as to all
portions of the Premises other than the Proposed Recapture space, this Lease
shall remain in full force and effect except that the Rent shall be reduced pro
rata. Landlord and Tenant shall promptly enter into an amendment to this Lease
setting forth the new Rentable Area of the Premises and the consequent reduction
in Base Rent and Additional Rent. In the event Landlord does not exercise its
right to terminate this Lease with respect thereto, Tenant shall be entitled to
seek an acceptable assignee or subtenant for the Proposed Recapture Space,
subject to Landlord's consent pursuant to Article 14.2 above.

                   14.6.   An assignment within the meaning of this Lease is
intended to comprehend not only the voluntary action of Tenant, but also any
involuntary action to include without limitation any levy or sale on execution
or other legal process against the leasehold, and every assignment of the
leasehold for the benefit of creditors, and the filing or any petition or order
described in Article 31.1.3 below.

                   14.7.   No subletting or assignment with or without
Landlord's consent shall in any way relieve or release Tenant from liability for
the performance of all terms, covenants and conditions of this Lease.
Furthermore, no assignment will be valid unless the assignee shall execute and
deliver to Landlord an assumption of liability agreement in form reasonably
satisfactory to Landlord, including an assumption by the assignee of all of the
obligations of Tenant and the assignee's ratification of and agreement to be
bound by all the provisions of this Lease; and no subletting will be valid
unless the subtenant first enters into a written agreement that subordinates
such sublease to this Lease and confirms that no provision of such sublease is
inconsistent with the terms and conditions of this Lease. Any successors and
assigns of the Tenant named as Tenant on page I of this Lease shall have the
same obligations and liabilities as it would have possessed had it originally
executed this Lease as the Tenant; any rights, privileges or powers under this
Lease shall inure to the benefit of any such successor or assignee of Tenant,
immediate or remote, only if the assignment to such assignee or successor has
been approved in writing by Landlord or, under the terms of this Lease, is an
assignment for which no approval is required, and such successor or assignee
shall have executed and delivered to Landlord the written documents required by
Landlord referred to hereinbefore, and each and every person hereinabove named
as the Tenant shall be bound jointly and severally by the terms, covenants and
agreements contained herein.



                                       23



                   14.8.   Although the Permitted Use shall in all events be
limited to that set forth in Article 1.8, for the purpose of protecting any
mortgagee or other investor in the Property from having made certain unfavorable
or unlawful investments, it is agreed that Tenant shall not enter into any
assignment, sublease, license, concession or other agreement for use, occupancy
or utilization of the whole or any part of the Premises with or without
Landlord's consent, which provides for rental or other payment for such use,
occupancy or utilization based, in whole or in part, on the net income or net
profits derived by any person or entity from the space leased, used, occupied or
utilized (other than an amount based on a fixed percentage or percentages of
gross receipts or sales), and any such purported assignment, sublease, license,
concession or other agreement shall be absolutely void and ineffective as a
conveyance or creation of any right or interest in the possession, use,
occupancy or utilization of any part of the Premises.

         15.       Alterations.

                   15.1.   Except for Tenant Work which shall be governed by the
Tenant Design and Construction Process set forth on Exhibit "C", Tenant
covenants to make no alteration, addition or improvement to the Premises without
first submitting a detailed description thereof to Landlord and obtaining
Landlord's written approval thereof, which shall not be unreasonably withheld,
conditioned or delayed, except that Landlord's written approval shall not be
required for painting, wall coverings, carpeting or decorations or for minor,
nonstructural improvements, additions or alterations valued at less than $35,000
in each instance at the time thereof and not adversely affecting the structural,
mechanical, electrical or plumbing systems, or any components thereof, of the
Buildings. Landlord agrees that Tenant may, at Tenant's sole expense and subject
to Landlord's prior approval (which approval will not be unreasonably withheld,
conditioned or delayed) as to size, equipment specifications, architectural
screening and engineering requirements, and subject to all local, county and
state rules, codes, ordinances and statutes, install and maintain: (i)
additional cooling towers or electrical generators on the roof of the
Centerpointe I Building, provided that space availability and structural
capacity permit such installation, and (ii) add air-cooled refrigeration
equipment within the garage level of the Centerpointe I Building or in close
proximity to the Centerpointe I Building and (iii) proprietary equipment or
antennae, HVAC units, communications and data transmission networks on the roof
of the Buildings so long as Tenant does not interfere with rights of other
tenants on the roof of the Centerpointe II Building.

                   15.2.   Provided that the proposed alteration, addition or
improvement does not in Landlord's reasonable judgment involve any modification
to the Buildings' exterior or any material modification to mechanical,
electrical or plumbing systems or components, or impairs the integrity of the
Buildings' structures, such approval shall not be unreasonably withheld or
delayed, but may be conditioned upon compliance with reasonable requirements of
Landlord, including, without limitation, the filing of mechanics' lien waivers
by Tenant's contractors or the posting of a bond to protect against mechanics
liens, and the submission of written evidence of adequate insurance coverage
naming Landlord as an additional insured thereunder.

                   15.3.   Landlord may withhold its approval in its absolute
and sole discretion with respect to each such alteration, addition or
improvement which Landlord reasonably determines involves any modification to
the Buildings' exterior or impairs the integrity of the Buildings' structures,
or involves any


                                       24



material modification to the Buildings' electrical, mechanical or plumbing
systems or any components thereof.

                   15.4.   Tenant shall not permit any financing statement or
statements to be filed with respect to any of the foregoing alterations,
additions or improvements. All alterations, additions or improvements made by
Tenant and all fixtures attached to the Premises (other than Tenant's trade and
business fixtures and equipment) shall remain at the Premises at the expiration
or sooner termination of this Lease and, upon their installation in the Premises
(unless such alterations, additions or improvements are composed of or contain a
Hazardous Substance), shall become the property of Landlord except that any or
all of the foregoing which may be designated by Landlord for removal in a notice
given at the time Landlord approves the original installation thereof in the
Premises shall be removed at the cost of Tenant before such expiration or sooner
termination and in such event, Tenant shall repair all damage to the Premises
caused by the installation or removal thereof, however, Tenant shall in no event
be required to remove customary items of office construction and finishing, such
as partitions, doors, light fixtures, carpeting and the like. Notwithstanding
anything in the foregoing to the contrary, Tenant shall in all events have the
right (but not the obligation) to remove any raised computer flooring or
supplementary HVAC installed in or about the Premises by or on behalf of Tenant
so long as Tenant restores the Premises following such removal.

                   15.5.   All such alterations, additions or improvements shall
be performed at Tenant's cost by one or more contractors approved by Landlord
(in its reasonable discretion), and shall be made in accordance with the
standards, procedures and requirements set forth in Exhibit "C" to the extent
that any such standards, procedures and requirements reasonably applies to the
proposed alterations, additions or improvements.

                   15.6.   Except as otherwise expressly provided herein, Tenant
shall not place, or cause or allow to be placed, any sign, advertising matter,
lettering, stand, booth, showcase or other article or matter outside of the
Premises, without the prior written consent of Landlord which may be withheld in
its sole discretion.

         16.       Mechanics' and Other Liens.

                   16.1.   Tenant covenants that it shall not (and has no
authority to) create or allow any encumbrance against the Premises, the Property
or the Buildings, or any part of any thereof or Landlord's interest therein.

                   16.2.   Tenant covenants that it shall not suffer or permit
to be created, or to remain, any lien or claim thereof (arising out of any work
done or services, material, equipment or supplies furnished for or at the
request of Tenant or by or for any contractor or subcontractor of Tenant) which
is or may become a lien upon the Premises, the Property or the Buildings, or any
part of any thereof or the income therefrom or any fixture, equipment or similar
property therein.

                   16.3.   If any lien or claim shall be filed, Tenant shall
within 15 days after Tenant receives notice of the filing thereof, cause the
same to be discharged of record by payment, deposit, bond or otherwise. If
Tenant shall fail to cause such lien or claim to be discharged and removed from
record (by bonding or otherwise) within that period, then, without obligation to
investigate the validity thereof and in addition to any other right or remedy
Landlord may have, Landlord may, but shall not be obligated to, contest the lien
or claim or discharge it by posting a


                                       25



bond, if that method is reasonably practicable, or, if posting a bond is not
reasonably practicable, by payment, deposit or otherwise. Any amounts so paid by
Landlord and all reasonable costs and reasonable expenses, including reasonable
attorneys' fees, incurred by Landlord in connection therewith, together with
interest at the Lease Interest Rate from the respective dates of Landlord's
making of the payment or incurring of the cost or expense, shall constitute
Additional Rent payable by Tenant under this Lease and shall be paid by Tenant
to Landlord promptly on demand.

                   16.4.   Notwithstanding anything contained herein to the
contrary, nothing contained in or contemplated by this Lease shall be deemed or
construed in any way to constitute the consent or request on the part of
Landlord for the performance of any work or services or the furnishing of any
materials for which any lien could be filed against the Premises or the
Buildings or the Property or any part of any thereof, nor as giving Tenant any
right, power, or authority (beyond those set forth in this Lease) to contract
for or permit the performance of any work or services or the furnishing of any
materials for which any lien could be filed against the Premises, the Buildings,
or the Property or any part of any thereof.

         17.       Landlord's Right to Enter. Landlord has the right, and Tenant
will permit Landlord, its agents, employees and any other persons authorized by
Landlord in writing, to enter the Premises at any time in case of an emergency;
to enter the Premises at any reasonable time after reasonable prior notice if
Landlord shall so elect for making alterations, improvements or repairs to the
Buildings or for any purpose in connection with the operation or maintenance or
financing of the Buildings and, if Tenant abandons the Premises, then at any
time to re-enter and renovate the Premises; in any event, no such entry or
renovation shall be considered as a deprivation of Tenant's use of the Premises
or shall give rise to any abatement of Rent and Landlord shall use its best
efforts to avoid any material interference with Tenant's use and enjoyment of
the Premises and whenever reasonably possible cause such entry to occur during
hours other than Standard Operating Hours. In addition, to the extent that
Tenant gives Landlord prior written notice thereof, Landlord shall comply with
Tenant's reasonable security requirements and any security restrictions imposed
by Tenant's governmental or private-sector clients that may apply to any
portion(s) of the Premises.

         18.       Certain Rights Reserved by Landlord. Landlord waives no
rights, except those that may be specifically and expressly waived pursuant to
the terms of this Lease, and explicitly retains all other rights, including,
without limitation, the following rights, each of which Landlord may exercise
without liability to Tenant for damage or injury to property, person or business
on account of the exercise thereof, and the exercise of any such rights shall
not be deemed to constitute an eviction or disturbance of Tenant's use or
possession of the Premises (provided that Landlord shall use its best efforts to
avoid any material interference with Tenant's use and enjoyment of the Premises)
and shall not give rise to any claim for set-off or abatement of Rent or any
other claim:

                   18.1.   To install, affix and maintain any and all signs
which comport with the character of a first class building on the exterior and
on the interior of the Centerpointe II Building or on the exterior or interior
of the Centerpointe I Building if Tenant is no longer the largest tenant of the
Centerpointe I Building.



                                       26



                   18.2.   To decorate or to make repairs, alterations,
additions, or improvements, whether structural or otherwise, in and about the
Buildings, or any part thereof, and for such purposes to enter upon the Premises
(in accordance with the terms of Article 17 above), and during the continuance
of any of such work, to temporarily close doors, entry ways, public space and
corridors in the Buildings and to interrupt or temporarily suspend services or
use of facilities, all without affecting any of Tenant's obligations hereunder,
so long as the Premises are reasonably accessible and usable.

                   18.3.   To furnish door keys for the entry door(s) in the
Premises at the commencement of the Lease and to retain at all times, and to use
in appropriate instances, keys to all doors within and into the Premises (except
as provided below). Tenant agrees to change no locks, and not to affix locks on
doors without the prior written consent of the Landlord, which consent Landlord
will not unreasonably withhold or delay so long as Tenant gives to Landlord
duplicate keys for any changed locks (subject to any security requirements for
Tenant's clients, which may prohibit delivery of duplicate keys for portions of
the Premises). Upon the expiration of the Term or Tenant's right to possession,
Tenant shall return all keys to Landlord and shall disclose to Landlord the
combination of any safes, cabinets or vaults left in the Premises. Tenant shall
have the right to install an access-control system for the Premises (including
interior areas within the Premises), which may be separate from Landlord's
access-control system for the Buildings or may be an extension of Landlord's
system (at Tenant's expense) to cover the Premises so long as such system does
not interfere with the other access control systems for the Buildings and does
not limit Landlord's access to the Premises as permitted under Article 17 above.
If Tenant extends Landlord's access-control system for the Buildings to cover
the Premises, Landlord shall not thereafter replace the Buildings'
access-control system or change it in a way that impairs the functioning of
Tenant's system without Tenant's prior written approval which approval shall not
be unreasonably withheld or delayed.

                   18.4.   To approve all window coverings used in the
Buildings.

                   18.5.   To approve the weight, size and location of safes,
vaults and other heavy equipment and articles in and about the Premises and the
Buildings so as not to exceed the legal load per square foot designated by the
structural engineers for the Buildings, and to require all such items and
furniture and similar items to be moved into or out of the Buildings and
Premises only at such times and in such manner as Landlord shall reasonably
direct in writing. Tenant shall not install or operate machinery or any
mechanical devices of a nature not directly related to Tenant's ordinary use, as
limited by the Permitted Use, of the Premises without the prior written consent
of Landlord. Movements of Tenant's property into or out of the Buildings or
Premises and within the Buildings are entirely at the risk and responsibility of
Tenant.

                   18.6.   To regulate (pursuant to reasonable rules and
regulations) delivery of supplies and the usage of the loading docks, receiving
areas and freight elevators.

                   18.7.   To enter the Premises in accordance with Article 17,
and in the last year of the Term, to show the Premises to prospective tenants at
reasonable times after reasonable prior


                                       27



notice to Tenant and, if abandoned, to show the Premises at any time and to
prepare the Premises for re-occupancy.

                   18.8.    To erect, use and maintain pipes, ducts, wiring and
conduits, and appurtenances thereto, in and through the Premises at reasonable
locations.

                   18.9.    To enter the Premises in accordance with Article 17
at any reasonable time to inspect the Premises and to make repairs or
alterations as Landlord deems necessary, with due diligence and minimum
disturbance.

                   18.10.   To grant to any person or to reserve unto itself the
right to conduct any business or render any service in the Buildings.

         19.       Landlord's Liability; Rights.

                   19.1.    It is expressly understood and agreed by Tenant that
none of Landlord's covenants, undertakings or agreements are made or intended as
personal covenants, undertakings or agreements by Landlord or its partners,
shareholders or trustees, or any of their respective partners, shareholders or
trustees, and any liability for damage or breach or nonperformance by Landlord
(that is not covered by Landlord's liability insurance, which shall not in any
way abrogate the waivers set forth in Article 21.4) shall be collectible only
out of Landlord's interest in the Buildings and the rents, the net proceeds of
sale arising therefrom, and insurance and condemnation proceeds actually
collected by Landlord, and no personal liability is assumed by, nor at any time
may be asserted against, Landlord or its partners, shareholders or trustees or
any of its or their partners, shareholders, trustees, officers, agents,
employees, legal representatives, successors or assigns, if any, all such
liability, if any, being expressly waived and released by Tenant.

                   19.2.    The Landlord named on page 1 of this Lease and any
subsequent owners of such Landlord's interest in the Buildings, as well as their
respective heirs, personal representatives, successors and assigns shall each
have the same rights, remedies, powers, authorities and privileges, and
obligations and liabilities, as it would have had had it originally signed this
Lease as Landlord, but any such person, whether or not named herein, shall have
no liability hereunder for acts occurring after it ceases to hold such interest,
provided all such liability arising from and after such date is assumed in a
written agreement between Landlord and such successor owner.

         20.       Unilateral Amendment. Landlord shall have the right at any
time, and from time to time, during the Term of this Lease, to unilaterally
amend the provisions of this Lease if Landlord is advised by its counsel that
all or any portion of the monies paid by Tenant to Landlord hereunder are, or
may be deemed to be, unrelated business income within the meaning of the United
States Internal Revenue Code or regulations issued thereunder, and Tenant agrees
that it will execute all documents or instruments necessary to effect such
amendment or amendments, provided that no such amendment shall result in Tenant
having to pay a larger sum of money on account of its occupancy of the Premises
under the terms of this Lease as so amended, and provided further that no such
amendment or amendments shall result in Tenant receiving under the



                                       28



provisions of this Lease less services that it is entitled to receive, nor
services of a lesser quality nor otherwise materially and adversely affect the
rights of Tenant under this Lease.

         21.       Insurance.

                   21.1.    Avoidance of Acts Which Increase Insurance Risk.
Landlord and Tenant each covenant that it will not do or commit, or suffer or
permit to be done or committed, any act or thing as a result of which any policy
of insurance of any kind on or in connection with the Buildings or the Property
or any part thereof shall become void or suspended, or the insurance risk on the
Buildings or the Property or any part thereof shall (in the opinion of any
insurer or proposed insurer) be rendered more hazardous. Tenant shall pay as
Additional Rent, within 30 days after being billed therefor, the amount of any
increase of premiums for such insurance resulting from any breach of this
covenant.

                   21.2.    Tenant's Insurance Coverage.  Tenant covenants that
it shall maintain throughout the Term, at Tenant's expense, policies of (i)
commercial general public liability insurance having initial limits of not less
than $5,000,000 per occurrence and annual aggregate combined single limit for
bodily injury and property damage, with a severability of interest endorsement,
and with increases in such limits as may from time to time be commercially
common for tenants of first-class office buildings in the Northern Virginia
area, and (ii) all-risk or fire and extended coverage insurance upon Tenant's
personal property and leasehold improvements in the Premises for the full
replacement value of such personal property and leasehold improvements. Such
policies shall name Landlord (and, if available, Landlord's mortgagees from time
to time) as an additional insured party and shall provide that the policies
shall not be cancelable without at least 30 days' prior written notice to
Landlord and shall be issued by insurers licensed to do business in Virginia and
having a Best's rating of A-XII or higher. Tenant shall furnish Landlord with
certificates of insurance to evidence the existence of such coverage.

                   21.3.    Landlord's Insurance Coverage.  Landlord shall
maintain throughout the Term "all-risk" insurance upon the Buildings. Landlord's
property insurance shall include replacement cost coverage and an agreed amount
endorsement, and shall provide for a commercially reasonable "deductible" for
first class office buildings in the Northern Virginia area. Landlord shall also
carry (or cause to be carried) commercial general liability insurance covering
Landlord and its managing agent having limits of not less than $5,000,000 annual
aggregate combined single limit for bodily injury and property damage and with
increases in such limits equal to any increases from time to time in Tenant's
limits pursuant to Article 21.2 above. Landlord's liability policy shall name
Tenant as an additional insured party. All of Landlord's policies shall be
issued by insurers licensed to do business in Virginia and having a Best's
rating of A-XII or higher. Landlord shall furnish Tenant with certificates of
insurance to evidence the existence of such coverage. The cost of the premiums
for such insurance and of any endorsements thereto shall, for purposes of
Article 7 hereof, be part of the Annual Operating Costs.

                   21.4.    Waiver of Subrogation.  Notwithstanding anything in
this Lease to the contrary, each party hereto hereby releases the other party,
its agents and employees, to the extent


                                       29



the releasing party is, or is required hereunder to be, insured under its
insurance policies, from any and all liability for any loss or damage which may
be inflicted upon the property of such party, notwithstanding that such loss or
damage shall have arisen out of the negligent or other tortious act or omission
of the other party, its agents or employees. Each party hereto shall cause a
clause to be included in each and every policy of property insurance of the
party to the effect that such release shall not affect the right of the insured
to recover thereunder, if such clause is available. If such a waiver of
subrogation cannot be obtained, the party undertaking to carry the insurance
shall notify the other party of such fact, and the other party shall have a
period of 30 days thereafter to place such insurance in companies which are
reasonably satisfactory to the notifying party and will issue such insurance
with waiver of subrogation.

         22.       Fire or Other Casualty.

                   22.1.    Casualty to Centerpointe II Premises.  If the
Centerpointe II Premises (including machinery or equipment used in the operation
of the Centerpointe II Premises) shall be damaged by fire or other casualty
which casualty renders all or a material portion of the Centerpointe II Premises
untenantable, and Landlord elects not to rebuild or restore the Centerpointe II
Premises for any reason, but rather to cease operating the Centerpointe II
Building and to terminate the leases of the tenants therein, the Lease will
terminate as to the Centerpointe II Premises only (with an equitable abatement
of Rent as of the date of the casualty), but Tenant shall have no right to
terminate the Lease for the balance of the Premises in the Centerpointe I
Building provided, however, that (i) American Management Systems, Inc., or (ii)
any assignee of its entire interest in this Lease, or (iii) any sublessee of 90%
or more of the Premises for substantially all of the Term, or (iv) any sublessee
whose sublease term was due to expire less than 36 months following the date of
casualty and there shall be remaining at least 72 months in the Term (any party
in clauses (i) - (iv) above is herein a "Substitute Space Tenant") shall have
the right to lease "Substitute Space" (as hereinafter defined) for the balance
of the Term and Landlord shall have the obligation to pay to such Substitute
Space Tenant the "Substitute Space Differential" (as hereinafter defined) for
the balance of the Term. For purposes of this Article 22.1, the term "Substitute
Space" shall mean office building rental space in the Fair Oaks area of Fairfax
County or otherwise within a one and one-half driving mile radius of the
Centerpointe II Building, or to the South at the intersection of Waples Mill and
Random Hills Road, and of sufficient square footage to accommodate the rentable
square footage occupied by the Substitute Space Tenant in the Centerpointe II
Building in blocks of a full floor or more and otherwise be reasonably
equivalent in quality, features and on-site amenities (except that parking may
be surface lot only) to the Centerpointe II Premises. For purposes of this
Article 22.1, the term "Substitute Space Differential" shall mean the then
present value of the difference between: (i) the ' then base monthly rental and
additional monthly rental payable for the Substitute Space by the Substitute
Space Tenant (plus reasonable moving costs and the cost to build out the
Substitute Space in a manner that is equivalent to the Centerpointe II Premises)
for the remainder of the Term (but not any unexercised renewal terms), and (ii)
the Base Rent and Additional Rent payable under this Lease for the remainder of
the Term (but not any unexercised renewal terms). Any disputes between Landlord
and Tenant regarding the determination of Substitute Space or Substitute Space
Differential shall be determined by arbitration in accordance with Article 65 of
this Lease. If Tenant reasonably determines that no Substitute Space is then
obtainable (the reasonableness of


                                       30



which determination Landlord may challenge by arbitration pursuant to Article 65
below) then, notwithstanding anything in the foregoing to the contrary, Tenant
shall have the right to terminate this Lease with respect to both the
Centerpointe I Premises and the Centerpointe II Premises.

                   22.2.    Casualty To Centerpointe I Building: Restoration:
Landlord's Right to Terminate

                   22.2.1.  Except as provided in this Article 22.2, if the
Centerpointe I Building (including machinery or equipment used in the operation
of the Centerpointe I Building) shall be damaged by fire or other casualty, then
if permitted by Landlord's mortgagees, and only to the extent that there are
available insurance proceeds, Landlord shall be obligated to repair and restore
the same with reasonable promptness, subject to reasonable delays for insurance
adjustments and to delays caused by matters beyond Landlord's reasonable
control; provided, however, that Landlord shall have no duty to repair or
restore any personal property, or any alterations, additions, improvements or
decorations not originally installed pursuant to the Tenant Work and paid for
with the Concession Fund.

                   22.2.2.  However, if (a) the damage by fire or other casualty
renders all or a substantial part of the Centerpointe I Building untenantable
and occurs at a time such that following the date that the restoration and
repair work is reasonably anticipated to be completed less than 24 months of the
Term will remain; or (b) such fire or other casualty renders fifty percent (50%)
or more of the Rentable Area of the Centerpointe I Building untenantable and
Landlord elects to cease operating the Centerpointe I Building; then in any such
event, Landlord shall have the right to terminate this Lease (with equitable
prorations of Rent being made for Tenant's possession of any tenantable portions
of the Premises subsequent to the date of such damage and prior to the effective
date of such termination) upon giving written notice to Tenant at any time
within 90 days after the date of such damage

                   22.2.3.  If pursuant to Article 22.2.2(a) hereof, Landlord
elects not to repair or restore, Tenant may nullify such election pursuant to
such subsection if Tenant, within 30 days after the date of receipt of
Landlord's notice of election to terminate, exercises any available option to
extend the Term of this Lease for a Renewal Period such that more than 24 months
of the Term will remain after the date the restoration or repair work is
reasonably anticipated to be complete.

                   22.2.4.  Landlord shall have no liability to Tenant for, and
Tenant shall not be entitled to terminate this Lease by virtue of, any delays in
completion of repairs and restoration. Rent, however, shall equitably abate as
to those portions of the Premises as are, from time to time, untenantable as a
result of such damage.

                   22.3     Tenant's Right to Terminate For Centerpointe I
Building Casualty. In the event there shall occur any fire or other casualty
to the Centerpointe I Building after the Lease Commencement Date, Tenant shall
have the right to terminate this Lease in accordance with this Article 22.3. If
the damage by fire or other casualty renders all or a substantial part of the
Centerpointe I Building untenantable and occurs at a time such that following
the date that the restoration and repair work is reasonably anticipated to be
completed, less than 24 months of the Term will remain, Tenant shall have the
right to terminate this Lease. In all other casualty situations, if substantial


                                       31



completion of the restoration of the Centerpointe I Building does not occur, or
in Landlord's reasonable judgment will not occur, within 365 days after the fire
or other casualty (which 365-day period shall be extended for up to an
additional year to the extent of any delay caused by strikes, lockouts, acts of
god, acts of war or other occurrences beyond Landlord's control), Landlord shall
so notify Tenant in writing, which notice shall include Landlord's reasonable
estimate of the date of substantial completion of the restoration. Tenant, by
giving written notice of termination within 15 business days after its receipt
of Landlord's notice, shall have the right to terminate this Lease effective as
of such date not later than 45 business days after Tenant's receipt of
Landlord's notice, as Tenant may specify in such notice. In the event of such
termination, neither party shall be liable to the other for any liability
relating to the period after termination. If Tenant does not terminate this
Lease as aforesaid, and the substantial completion of the restoration does not
occur by the estimated date of substantial completion contained in the aforesaid
notice, Landlord shall provide within 10 business days after a determination is
made that substantial completion will not occur by the estimated date a second
notice estimating the extended date of substantial completion, and Tenant shall
again have the right, exercisable only by written notice given within 15
business days after the receipt of Landlord's notice, to terminate this Lease
within the 45-day time period set forth above in this Article 22.3. In each
instance in which Tenant elects not to exercise its right to terminate as
provided in this Article 22.3, such right to terminate, following the same
procedure and schedule, shall again arise if substantial completion has not
occurred by the estimated date of substantial completion set forth in the notice
upon which Tenant's previous election not to terminate was based.

         23.       Waiver of Claims; Indemnification.

                   23.1.    Neither Landlord nor any partner, shareholder or
trustee in Landlord shall be held responsible for, and each is hereby expressly
relieved from, any and all liability by reason of any injury, loss, or damage to
any person or property in or about Tenant's Control Area (as defined in Article
52 below) due to any cause whatever, or arising from Tenant's use of the roof,
garage and other facilities in Landlord's Control Area permitted pursuant to
Articles 9.1.3 and 15.1, except for liability arising from the acts within the
Tenant's Control Area of Landlord's cleaning personnel or Landlord's building
engineers, and whether the loss, injury or damage be to the person or property
of Tenant or any other person, unless due to the gross negligence of Landlord,
its servants or employees. Tenant further agrees to indemnify, defend and save
Landlord and each partner, shareholder or trustee in Landlord harmless from and
against all claims by any employee or invitee of Tenant made on account of such
injury, loss or damage (unless due to the gross negligence of Landlord, its
servants and employees), including but not limited to reasonable attorneys' fees
and other legal expenses.

                   23.2.    Neither Tenant nor any partner, shareholder or
trustee in Tenant shall be held responsible for, and each is hereby expressly
relieved from, any and all liability by reason of any injury, loss or damage to
any person or property in or about Landlord's Control Area (as defined in
Article 52 below), due to any cause whatsoever, or arising from the acts within
Tenant's Control Area of Landlord's cleaning personnel or Landlord's building
engineers, except for liability arising from Tenant's use of the roof, garage
and other facilities in Landlord's Control Area permitted pursuant to Articles
9.1.3 and 15.1, and whether the loss, any injury or damage be


                                       32



to the person or property of Landlord, or any other person, unless due to the
gross negligence of Tenant, its servants or employees. Landlord further agrees
to indemnify, defend and save Tenant harmless from and against all claims by any
person made on account of such injury, loss or damage (unless due to the gross
negligence of Tenant, its servants or employees), including but not limited to
reasonable attorneys' fees and other legal expenses.

         24.       Condemnation.

                   24.1.    If the whole or a substantial part of the
Centerpointe I Building is taken or condemned for a public or quasi-public use
under any statute or by right of eminent domain by any competent authority or
sold in lieu of such taking or condemnation, such that in the opinion of
Landlord the Centerpointe I Building is not economically operable as before
without substantial alteration or reconstruction, this Lease shall automatically
terminate on the date that the right to possession shall vest in the condemning
authority (the "Taking Date"), with Rent being adjusted to said Taking Date, and
Tenant shall have no claim against Landlord for the value of any unexpired term
of this Lease. Tenant shall have no claim against Landlord and no claim or right
to any portion of any amount that may be awarded as damages or paid as a result
of any taking, condemnation or purchase in lieu thereof, except for moving
expenses, if any, which may be separately awarded to tenants under Virginia or
federal law to the extent that such award does not reduce the amount to be
awarded or paid to Landlord; all other rights of Tenant to any award are hereby
assigned by Tenant to Landlord. If the whole or a substantial part of the
Centerpointe II Premises is taken or condemned for a public or quasi-public use
under any statute or by right of eminent domain by any competent authority or
sold in lieu of such taking or condemnation, such occurrence shall be treated as
though a casualty had occurred to the Centerpointe II Premises and Landlord had
elected not to rebuild or restore the Centerpointe II Premises, as described in
Article 22.1 above.

                   24.2.    If any part of the Premises is so taken or
condemned, this Lease shall automatically terminate as to the portion of the
Premises so taken or condemned, as of the Taking Date, and this Lease shall
continue in full force as to the remainder of the Premises, with Rent abating
only to the extent of the Premises so taken or condemned.

                   24.3.    In the event of any temporary eminent domain taking
of the Premises or any part thereof for temporary use, this Lease shall not be
affected in any manner, the Term shall not be reduced, and the Tenant shall
continue to pay in full the Base Rent, Additional Rent and all other sums of
money and charges in this Lease reserved and provided to be paid by Tenant.
Tenant shall be entitled to receive for itself such portion of any eminent
domain award made for such temporary use with respect to the period of the
taking which is within the Term; provided that if such temporary taking shall
remain in full force at the expiration or earlier termination of this Lease, the
award shall be apportioned between Landlord and Tenant in proportion to the
respective portions of the period of temporary taking which falls within the
Term and which falls outside the Term.

         25.       Holding Over.


                                       33



                   25.1.    If Tenant or any person claiming through Tenant
shall continue to occupy the Premises after the expiration or earlier
termination of the Term or any renewal thereof without Landlord's written
consent, then Landlord shall be entitled to recover from Tenant compensation for
such use and occupancy at a rate per month equal to (i) 150% of the annual Base
Rent plus (ii) 1/12 of the annual Additional Rent which would have been payable
had this Lease been renewed for a period of 12 full calendar months following
such expiration or earlier termination, on the terms and conditions in effect
immediately prior thereto. Neither Landlord's demand nor Landlord's receipt of
the aforesaid compensation for use and occupancy shall be deemed to provide
Tenant with any right to any use, occupancy or possession of the Premises for
any period beyond which such compensation has been demanded and paid.

                   25.2.    The provisions of this Article 25 shall not be
deemed to limit or constitute a waiver of any other rights of remedies of
Landlord provided herein or at law.

         26.       Covenant of Quiet Enjoyment. Landlord covenants that Tenant,
on paying the Rent and all other charges or payments herein reserved and on
keeping, observing and performing all the other terms, covenants, conditions,
provisions and agreements herein contained on the part of Tenant to be kept,
observed and performed, shall, during the Term, peaceably and quietly have, hold
and enjoy the Premises subject to the terms, covenants, conditions, provisions
and agreements hereof.

         27.       Relocation of Tenant.  Intentionally Omitted.

         28.       Condition of Premises. The taking of possession of each
segment of the Premises by Tenant shall be conclusive evidence, as against
Tenant, that each such segment of the Premises was in good and satisfactory
condition at the time such possession was so taken, subject to (i) completion of
any Base Building Modifications set forth on Exhibit "B" that have not been
completed by the date of delivery of any segment of the Premises, (ii) latent
defects, provided that Tenant so notifies Landlord within one (1) year-of the
Lease Commencement Date, as to the Initial Space, and within one (1) year of the
applicable Subsequent Lease Commencement Date, as to Subsequent Space, or (iii)
defects other than latent defects identified by Tenant in a notice given to
Landlord within thirty (30) days of the Lease Commencement Date, as to the
Initial Space, and within thirty (30) days of any applicable Subsequent Lease
Commencement Date, as to Subsequent Space.

         29.       No Third Party Beneficiaries. Notwithstanding anything to the
contrary contained herein, no provision of this Lease is intended to benefit any
party other than the signatories hereto and their permitted heirs, personal
representatives, successors and assigns, and no provision of this Lease shall be
enforceable by any other party.

         30.       Transfer of Landlord's Interest. In the event of any sale or
other conveyance or transfer of Landlord's interest in a Building or the
Buildings, the transferor shall be and hereby is entirely free and relieved of
all covenants and obligations of Landlord hereunder prior to the date of
transfer as to the Building or Buildings transferred, provided that the
transferee at any such sale or conveyance or transfer (subject to the limitation
of Landlord's liability in Article 19 of this Lease) shall have assumed and
agreed in a written agreement with Landlord to carry out any and


                                       34



all covenants and obligations of Landlord hereunder arising or continuing from
and after the date of transfer.

         31.       Default; Landlord's Remedies.

                   31.1.    Defaults. If any of the following shall occur, such
occurrence shall constitute a default (which term, unless expressly noted
otherwise in this Lease, shall refer only to the circumstance that exists after
the giving of any notice and the expiration of any cure period provided for
herein) hereunder:

                   31.1.1.  Tenant does not pay in full when due any installment
of Rent or any other charge or payment whether or not herein included as Rent,
and such failure continues for ten (10) days after written notice from Landlord
specifying such failure, provided, however, that Landlord shall not be required
to give, and Tenant shall not be entitled to the benefit of, any such notice or
grace period more than two (2) times in any twelve (12) month period for late
payments of Monthly Installments of Base Rent and Additional Rent,

                   31.1.2.  Tenant violates or fails to perform or otherwise
breaks any covenant, agreement or condition herein contained or any other
obligation of Tenant to Landlord, and such violation or failure continues for
thirty (30) days after written notice from Landlord specifying such violation or
failure (or such longer period, as may be necessary if such violation or failure
cannot reasonably be cured within said thirty (30) day period but Tenant is
diligently and in good faith pursuing such cure and such violation or failure is
reasonably capable of a cure i as determined in Landlord's reasonable judgment),

                   31.1.3.  Tenant becomes the subject of commencement of an
involuntary case under the federal bankruptcy law as now or hereafter
constituted, or there is filed a petition against Tenant seeking reorganization,
arrangement, adjustment or composition of or in respect of Tenant under the
federal bankruptcy law as now or hereafter constituted, or under any other
applicable federal or state bankruptcy, insolvency, reorganization or other
similar law, or seeking the appointment of a receiver, liquidator or assignee,
custodian, trustee, sequestrator (or similar official) of Tenant or any
substantial part of its property, or seeking the winding-up or liquidation of
its affairs and such involuntary case or petition is not dismissed within 90
days after the filing thereof, or if Tenant commences a voluntary case or
institutes proceedings to be adjudicated a bankrupt or insolvent, or consents to
the institution of bankruptcy or insolvency proceedings against it, under the
Federal bankruptcy laws as now or hereafter constituted, or any other applicable
Federal or state bankruptcy or insolvency or other similar law, or consents to
the appointment of or taking possession by a receiver or liquidator or assignee,
trustee, custodian, sequestrator (or other similar official) of Tenant or of any
substantial part of its property, or makes any assignment for the benefit of
creditors or admits in writing its inability to pay its debts generally as they
become due or fails to generally pay its debts as they become due or if Tenant
or its stockholders or Board of Directors or any committee thereof takes any
corporate action in furtherance of any of the foregoing, then


                                       35



                   31.2.    Remedies.  In the event of any such default set
forth in Article 31.1 above, and, at the sole option of Landlord, Landlord may
pursue any one or more of the following remedies:

                   31.2.1.  Tenant's right of possession shall thereupon cease
and terminate, and to the extent permitted by law Landlord shall be entitled to
the possession of the Premises and to reenter the same without demand of rent or
demand of possession of said Premises and may forthwith proceed to recover
possession of the Premises by process of law, any notice to quit being hereby
expressly waived by Tenant. In the event of such re-entry by process of law,
Tenant nevertheless agrees to remain answerable for any and all damage,
deficiency or loss of Rent which Landlord may sustain by such re-entry,
including reasonable attorney's fees and court costs. If, under the provisions
hereof, seven (7) days summons or other applicable summary process shall be
served, and a compromise or settlement therefor shall be made, such action shall
not be constituted as a waiver of any breach of any covenant, condition or
agreement herein contained. No waiver of any breach of any covenant, condition
or agreement, herein contained, on one or more occasions shall operate as a
waiver of the covenant, condition or agreement itself, or of any subsequent
breach thereof. No provision of this Lease shall be deemed to have been waived
by Landlord unless such waiver shall be in writing signed by Landlord.

                   31.2.2.  Should this Lease be terminated before the
expiration of the Term of this Lease by reason of Tenant's default, the Premises
may be relet by Landlord for such rent and upon such terms as are reasonable
under the circumstances. If the full Rent reserved under this Lease (and any of
the costs, expenses or damages indicated below) shall not be realized by
Landlord, Tenant shall be liable for all damages sustained by Landlord,
including, without limitation, deficiency in Rent, reasonable attorneys' fees,
other reasonable collection costs, reasonable brokerage fees, and reasonable
expenses of placing the Premises in first-class rentable condition. Landlord, in
putting the Premises in good order or preparing the same for re-rental, may, at
Landlord's option, make such alterations, repairs, or replacements in the
Premises as Landlord, in Landlord's sole judgment, considers advisable and
necessary for the purpose of reletting the Premises, and the making of such
alterations, repairs, or replacements shall not operate or be construed to
release Tenant from liability hereunder as aforesaid. Landlord shall in no event
be liable in any way whatsoever for failure to relet the Premises, or in the
event that the Premises are relet, for failure to collect the rent thereof under
such reletting. In no event shall Tenant be entitled to receive any excess, if
any, of such net rent collected over the sums payable by Tenant to Landlord
hereunder.

                   31.2.3.  Any damage or loss of Rent sustained by Landlord may
be recovered by Landlord, at Landlord's option, at the time of the reletting, or
in separate actions, from time to time, as said damage shall have been
ascertained by successive relettings, or, at Landlord's option, may be deferred
until the expiration of the Term of this Lease (in which event Tenant hereby
agrees that the cause of action shall not be deemed to have accrued until the
date of expiration of said Term). The provisions contained in this Article
31.2.3 shall be in addition to and shall not prevent the enforcement of any
claim Landlord may have against Tenant for anticipatory breach of the unexpired
Term of this Lease. All rights and remedies of Landlord under this Lease shall
be


                                       36



cumulative and shall not be exclusive of any other rights and remedies provided
to Landlord under applicable law.

                   31.2.4.  If under the provisions hereof Landlord shall
institute proceedings and a compromise or settlement thereof shall be made, the
same shall not constitute a waiver of any covenant, rule or regulation herein
contained nor of any of Landlord's rights hereunder. No waiver by Landlord of
any breach of any covenant, condition, agreement, rule or regulation itself, or
of any subsequent breach thereof.

                   31.2.5.  If, prior to the Rent Commencement Date, Tenant
notifies Landlord of or otherwise unequivocally demonstrates an intention to
repudiate this Lease, Landlord may, at its option, consider such anticipatory
repudiation a breach of this Lease. In such event, in addition to Landlord's
other remedies hereunder, Landlord may retain all Rent paid upon execution of
the Lease and the security deposit, if any, to be applied to damages of Landlord
incurred as a result of such repudiation, including without limitation
reasonable attorneys' fees, brokerage fees, costs of reletting, loss of Rent,
etc. and Landlord shall be entitled to recover all or any portion of the
Concession Fund theretofore disbursed to Tenant hereunder (which, when
collected, shall be credited against Tenant's other liabilities hereunder), and
Tenant shall indemnify, defend and hold Landlord harmless from and against the
claims of any contractors or materialmen performing the Tenant Work.

                   31.2.6.  If the Premises shall be deserted or vacated by
Tenant for thirty (30) consecutive days or more without notice to Landlord, and
Tenant shall have failed to make the current Rent payment, the Premises may be
deemed abandoned. Landlord may consider Tenant in default under this Lease and
may pursue all remedies available to it under this Lease or at law, including
the following:

                            (a)      If Tenant abandons the Premises as defined
above, Landlord may, at its option, enter into the Premises without being liable
for any prosecution therefor or for damages by reason thereof. In addition to
any other remedy, Landlord, as agent of Tenant, may relet the whole or any part
of the Premises for the whole or any part of the then unexpired Lease Term. For
the purposes of such reletting, Landlord may make any alterations or
modifications of the Premises considered desirable in its sole judgment.

                            (b)      If Tenant abandons the Premises as defined
above, any property that Tenant leaves on the Premises shall be deemed to have
been abandoned and may either be retained by Landlord as the property of
Landlord or may be disposed of at public or private sale in accordance with
applicable law as Landlord sees fit. The proceeds of any public or private sale
of Tenant's property, or the then current fair market value of any property
retained by Landlord, shall be applied by Landlord against (i) the expenses of
Landlord for removal, storage or sale of the property; (ii) the arrears of Rent
or future Rent payable under this Lease; and (iii) any other damages to which
Landlord may be entitled hereunder.

                            (c)      If Tenant abandons the Premises, as defined
above, Landlord may, upon presentation of evidence of a claim valid upon its
face of ownership or of a security interest


                                       37



in any of Tenant's property abandoned in the Premises, turn over such property
to the claimant with no liability to Tenant.

                   31.2.7.  Landlord may (but shall not be obligated to do so),
in addition to any other rights it may have in law or equity, following the
delivery of notices prescribed by Article 31.1 above, cure such default on
behalf of Tenant, and Tenant shall reimburse Landlord upon demand for all
reasonable costs incurred by Landlord in curing such default, including, without
limitation, reasonable attorneys' fees and other legal expenses, together with
interest thereon at the Lease Interest Rate, which costs and interest thereon
shall be deemed Additional Rent hereunder.

         32.       Remedies Cumulative. All remedies available to Landlord
hereunder and at law and in equity shall be cumulative and concurrent. No
termination of this Lease nor taking or recovering possession of the Premises
shall deprive Landlord of any remedies or actions against Tenant for Rent, for
charges or for damages for the breach of any covenant, agreement or condition
herein contained, nor shall the bringing of any such action for Rent, charges or
breach of covenant, agreement or condition, nor the resort to any other remedy
or right for the recovery of Rent, charges or damages for such breach be
construed as a waiver or release of the right to insist upon the forfeiture and
to obtain possession. No reentering or taking possession of the Premises, or
making of repairs, alterations or improvements thereto, or reletting thereof,
shall be construed as an election on the part of Landlord to terminate this
Lease unless written notice of such election be given by Landlord to Tenant. The
failure of Landlord to insist upon strict and/or prompt performance of the
terms, agreements, covenants and conditions of this Lease or any of them, and/or
the acceptance of such performance thereafter shall not constitute or be
construed as a waiver of Landlord's right to thereafter enforce the same
strictly according to the terms thereof in the event of a continuing or
subsequent default.

         33.       Expenses of Enforcement. Each party shall pay upon demand all
of the other party's costs, charges and expenses, including the reasonable fees
and out-of-pocket expenses of counsel, agents and others, incurred in any
litigation, negotiation or transaction in which the defaulting party causes the
other without the other's fault, to become involved or concerned.

         34.       Nonwaiver. No waiver of any provision of this Lease shall be
implied by any failure of either party to enforce any remedy allowed for the
violation of such provision, even if such violation is continued or repeated,
and no express waiver shall affect any provision other than the one(s) specified
in such waiver and only for the time and in the manner specifically stated. No
receipt of monies by Landlord from Tenant after the termination of this Lease
shall in any way alter the length of the Term or of Tenant's right of possession
hereunder or after the giving of any notice shall reinstate, continue or extend
the Term or affect any notice given to Tenant prior to the receipt of such
moneys, it being agreed that after the service of notice or the commencement of
a suit or after final judgment for possession of the Premises, Landlord may
receive and collect any Rent due, and the payment of said Rent shall not waive
or affect said notice, suit or judgment.

         35.       Subordination.

                   35.1.    Subject to the satisfaction of the conditions of
Article 58 below, this Lease shall be subject and subordinate at all times to
the lien of any mortgage, deed of trust and/or other encumbrance heretofore or
hereafter placed by Landlord upon the Premises or the Property and of


                                       38



all renewals, modifications, consolidations, replacements and extensions thereof
(all of which are hereinafter referred to collectively as a "Mortgage"), all
automatically and without the necessity of any further action on the part of
Tenant to effectuate such subordination. Tenant shall, at the request of any
person who may acquire Landlord's estate by foreclosure (or transfer in lieu of
foreclosure), attorn to such person, and shall execute, acknowledge and deliver,
upon demand by Landlord or any mortgage holder or its assignee, but in no event
later than fifteen (15) days after such demand, such further reasonable
instruments evidencing such subordination, and such further reasonable
instruments evidencing such attornment obligation, as shall be desired by such
Mortgage holder or its assignee.

                   35.2.    Anything contained in the foregoing provisions of
this Article 35 to the contrary notwithstanding, any such holder may at any time
subordinate, in whole or in part, its Mortgage to the operation and effect of
this Lease, without the necessity of obtaining Tenant's consent thereto, by
giving notice of the same in writing to Tenant, and thereupon this Lease shall
be deemed to be prior to such Mortgage without regard to their respective dates
of execution, delivery and/or recordation, and in that event, such holder shall
have the same rights with respect to this Lease as though this Lease were
executed, delivered and recorded prior to the execution and delivery of such
Mortgage.

                   35.3.    No person acquiring Landlord's estate by foreclosure
or transfer in lieu of foreclosure shall have any personal liability hereunder
or any liability whatsoever for the acts of the Landlord prior to any such
transfer or any liability for any deposits made by Tenant hereunder unless such
deposits have been transferred to such party; provided, however, that such party
shall have the liability to perform all of the Landlord's duties and obligations
arising or continuing thereafter, if any, that have not been performed as of the
date of transfer.

         36.       Paramount Lease. Subject to the satisfaction of the terms of
Article 58 below, if Landlord is or becomes lessee of a Building or the
Buildings or the land upon which they stand, then Tenant agrees that Tenant's
possession shall be that of a subtenant and subordinate to the interest of
Landlord's lessor, its heirs, personal representatives, successors and assigns
(such lessor and other persons being hereinafter collectively referred to as the
"Overlessor") without the necessity of any further action on the part of Tenant
to effectuate such subordination (provided that such change in status does not
affect any of Tenant's rights or Landlord's obligations under this Lease), but
notwithstanding the foregoing, if Landlord's tenancy shall terminate either by
expiration, forfeiture or otherwise, then, if Overlessor shall so request,
Tenant shall attorn to Overlessor and recognize Overlessor as Tenant's landlord
upon the terms and conditions of this Lease for the balance of the Term hereof
and any extensions or renewals hereof. Tenant shall execute, acknowledge and
deliver, upon demand by Landlord or any Overlessor, such further customary and
reasonable instruments evidencing such subordination of Tenant's right, title
and interest under this Lease to the interests of Overlessor, and such further
customary and reasonable instruments of attornment, as shall be desired by such
Overlessor. Landlord represents and warrants that the Property is not currently
subject to any ground lease or Overlease.

         37.       Legal Proceedings. It is mutually agreed by and between
Landlord and Tenant that (a) they hereby waive trial by jury in any action,
proceeding or counter-claim brought by either of


                                       39



the parties hereto against the other on any matter whatsoever arising out of or
in any way connected with this Lease, the relationship of Landlord and Tenant,
Tenant's use or occupancy of the Premises or claim of injury or damage, and (b)
in any action against Landlord by Tenant, or against Tenant by Landlord, the
reasonable legal fees of the prevailing party will be paid by the other party to
the action. The parties hereto consent to the jurisdiction of the courts of the
Commonwealth of Virginia and of the United States District Court of Virginia in
connection with any action, suit or proceeding arising out of or relating to
this Lease, and agree that venue shall lie only in said courts.

         38.       Interpretation.

                   38.1.    Gender; Plural Terms; Persons.  The masculine (or
neuter) pronoun and the singular number shall include the masculine, feminine
and neuter genders and the singular and plural numbers. A reference to person
shall mean a natural person, a trustee, a corporation, a partnership and any
other form of legal entity. All references in the singular or plural number
shall be deemed to have been made, respectively, in the plural or singular
number as well, as the context may require.

                   38.2.    Exhibits.  Each and every document or other writing
which is referred to herein as being attached hereto or is otherwise designated
herein as an exhibit hereto is hereby made a part hereof.

                   38.2.1.  Captions.  The captions of Articles, sections,
subsections and the Table of Contents are for convenience only; they are not
intended to indicate all of the subject matter in the text and they shall not be
deemed to limit, construe, affect or alter the meaning of any provisions of this
Lease and are not to be used in interpreting this Lease or for any other purpose
in the event of any controversy.

         39.       Severability. If any provision contained in this Lease shall,
to any extent, be invalid or unenforceable, the remainder of this Lease (and the
application of such provision to persons or circumstances, if any, other than
those in respect of which it is invalid or unenforceable) shall not be affected
thereby, and each and every other provision of this Lease shall be valid and
enforceable to the fullest extent permitted by law.

         40.       Notices. All notices required to be given by Landlord to
Tenant shall be sufficiently given by overnight courier service delivery against
written receipt or signed proof of delivery, or mailing the same by registered
or certified mail, return receipt requested, to Tenant's Address or to such
other person or persons and address or addresses as Tenant may from time to time
designate in writing and deliver to Landlord in accordance with this Article.
Notices given by Tenant to Landlord shall be sufficiently given by registered or
certified mail, return receipt requested, overnight express delivery service or
by courier service delivery against written receipt or signed proof of delivery,
to Landlord at Landlord's Address or to such other person and address as
Landlord may from time to time designate in writing and deliver to Tenant in
accordance with this Article. Notices may be given on behalf of either party by
its counsel.


                                       40



         41.       No Representation by Landlord. Landlord and Landlord's agents
have made no representation, agreements, conditions, warranties, understandings,
or promises, either oral or written, other than as herein set forth, with
respect to the Lease, Buildings, Property, or Premises, or otherwise.

         42.       Whole Agreement. This Lease, the exhibits, and any riders
attached hereto and forming a part hereof set forth all of the promises,
agreements, conditions, warranties, representations and understandings between
Landlord and Tenant relative to the Premises and this leasehold. No alteration,
amendment, modification, waiver, understanding or addition to this Lease shall
be binding upon Landlord or Tenant unless reduced to writing and signed by
Landlord and Tenant or by a duly authorized agent of Landlord or Tenant
empowered by a written authority signed by Landlord and/or Tenant (as the case
may be).

         43.       Security Deposit.  Intentionally Omitted.

         44.       Real Estate Broker. Landlord and Tenant each represent and
warrant to the other that it has dealt with no broker, agent or other
intermediary in connection with this Lease other than Julien J. Studley, Inc.
and Cushman & Wakefield of Virginia, and that insofar as it knows, no other
broker, agent or other intermediary negotiated this Lease or introduced Tenant
to Landlord or brought the Buildings to Tenant's attention for the lease of
space therein. Tenant recognizes Cushman & Wakefield of Virginia as its broker
of record for the Term of this Lease and authorizes Joshua Realty Corporation to
pay the commissions to Cushman & Wakefield of Virginia during the Term of this
Lease pursuant to an agreement of even date herewith and Landlord agrees that
Joshua Realty Corporation, as Landlord, shall be responsible for any commissions
payable to Julien J. Studley, Inc., with respect to this Lease, pursuant to a
separate agreement of even date herewith. Each party agrees to indemnify, defend
and hold the other and its partners, employees, agents, their officers and
partners, harmless from and against any claims made by any broker, agent or
other intermediary other than Julien J. Studley, Inc. and Cushman & Wakefield of
Virginia, with respect to a claim for broker's commission or fee or similar
compensation brought by any person in connection with this Lease, provided that
the indemnified party has not in fact retained such broker, agent or other
intermediary.

         45.       Inability to Perform. If Landlord or Tenant is delayed or
prevented from performing any of its obligations under this Lease by reason of
strike, labor troubles, or any cause whatsoever beyond its control, the period
of such delay or prevention shall be deemed added to the time herein provided
for the performance of any such obligation.

         46.       Corporate Entities. If Tenant is a corporation, each person
executing this Lease on behalf of Tenant hereby covenants and warrants that:
Tenant is a duly formed corporation qualified to do business in the state in
which the Premises is located; all Tenant's franchise and corporate taxes have
been paid to date; and such persons are duly authorized by such corporation to
execute and deliver this Lease on behalf of the corporation. Each person
executing this Lease on behalf of Landlord hereby covenants and warrants that:
Landlord is a duly formed corporation qualified to do business in the state in
which the Premises is located; all Landlord's franchise and


                                       41



corporate taxes have been paid to date; and such persons are duly authorized by
such corporation to execute and deliver this Lease on behalf of the corporation.

         47.       Recordation. At the time of execution of this Agreement,
Landlord and Tenant shall execute and acknowledge, in recordable form, for
notice and recording purposes only, a Memorandum of this Agreement, it being
expressly agreed that such Memorandum shall not supersede, add to or change this
Lease. The form of Memorandum is attached hereto as Exhibit "J" and Tenant may
cause the Memorandum to be recorded in the appropriate office for recording in
Fairfax County at Tenant's sole expense. Tenant covenants to execute and deliver
a termination of Memorandum upon the termination of this Lease, and Tenant
hereby appoints Landlord its attorney-in-fact to file any instrument to remove
or discharge from record any such Memorandum.

         48.       Time. Time is of the essence of this Lease and all of its
provisions.

         49.       Applicable Law. This Lease shall in all respects be governed
by the laws of the Commonwealth of Virginia.

         50.       Defined Terms. As used in this Lease, the following terms
have the meaning as set forth below, respectively:

                   50.1.    Affiliate.  Any corporation which is controlled by,
controlling, or under common control with Tenant. As used herein the term
"control" shall mean possession of the power, directly or indirectly, to vote
more than fifty percent (50%) of the voting securities having the ordinary power
for the election of directors.

                   50.2.    Buildings: The physical structures located at 4050
Legato Road and 4000 Legato Road, Fairfax, Virginia.

                   50.3.    Holidays: The following holidays:

                   50.3.1.  For the Centerpointe I Building

                   New Year's Day
                   Martin Luther King Jr. Day (in even-numbered years)
                   Washington's (President) Birthday
                   Memorial Day
                   Independence Day
                   Labor Day
                   Columbus Day (in odd-numbered years)
                   Thanksgiving Day
                   Day After Thanksgiving
                   Christmas Day

                   50.3.2.  For the Centerpointe II Building:

                   New Year's Day
                   Martin Luther King Jr. Day
                   Washington's (President) Birthday


                                       42


                   Memorial Day
                   Independence Day
                   Labor Day
                   Columbus Day
                   Veterans Day
                   Thanksgiving Day
                   Christmas Day

                   50.4.    HVAC Off-Hours Rate: For the Centerpointe I
Building, a rate which shall include only Landlord's actual labor costs and the
reasonable cost for additional wear and tear of Landlord's equipment. For the
Centerpointe II Building, a charge per floor equal to $45.00 per hour, and
$54.00 per hour on Holidays (with a flat rate of $25.00 per hour payable for
each additional floor), with a two (2) hour minimum, subject to adjustment in
accordance with any increases in Landlord's actual labor costs and the
reasonable cost of additional wear and tear of Landlord's equipment.

                   50.5.    Landlord: The Landlord named on page 1 of this Lease
and any subsequent owner of such Landlord's interest in the Buildings, as well
as their respective heirs, personal representatives, successors and assigns, all
subject to the provisions of Article 19.

                   50.6.    Lease Interest Rate: The lesser of (A) the Prime
Rate in effect from time to time plus 3%, or, (B) the maximum amount or rate
that Landlord lawfully may charge Tenant in such circumstances, if such a
maximum exists.

                   50.7.    Lease Taxes: Any tax, assessment, levy or other
charge (other than any income tax or the Fairfax County BPOL gross receipts or
gross expenditure taxes) by any federal, state or local law now or hereafter
imposed directly or indirectly upon Landlord with respect to this Lease or the
value thereof, or upon the Tenant's use or occupancy of the Premises, or upon
the Base Rent, Additional Rent or any other sums payable under this Lease or
upon this transaction.

                   50.8.    Ordinary Business Hours: Monday through Friday,
inclusive, from 8:00 a.m. to 7:00 p.m., in the Centerpointe I Building, and from
8:00 a.m. to 6:00 p.m., in the Centerpointe II Building, and Saturdays from 8:00
a.m. to 1:00 p.m. in both Buildings, with Holidays excepted.

                   50.9.    Prime Rate: The reference rate of interest as
published in the Money Rates section of the Wall Street Journal from time to
time, or if such reference rate is discontinued, such comparable rate as
Landlord reasonably designates by written notice to Tenant.

                   50.10.   Property: The Buildings and the land owned by
Landlord upon which they stand, as more particularly described on Exhibit "HI'
attached hereto.

                   50.11.   Real Estate Taxes: All real estate taxes and
assessments, general or special, ordinary or extraordinary, foreseen or
unforeseen (other than Lease Taxes) assessed or imposed upon the Buildings
and/or the Property. If, due to a future change in the method of taxation, any
franchise, income, profit or other tax, however designated, shall be levied or
imposed in substitution, in whole or in part, for (or in lieu of) any tax or
increase in any tax which would otherwise be included within the


                                       43



definition of Real Estate Taxes, then such other tax shall be deemed to be
included within Real Estate Taxes as defined herein. Any special assessments
which may be paid in installments shall be paid over the maximum number of
installments permitted without the imposition of any penalty. Except as provided
in the immediately-preceding sentence, Real Estate Taxes shall not include any
income, profit, franchise, capital stock, excise, estate, gift, succession,
transfer or recordation tax or levy.

                   50.12.   Rent: Additional Rent and Base Rent, collectively.

                   50.13.   Rentable Area of the Buildings: Deemed to be 203,630
square feet for each of the Centerpointe I Building and the Centerpointe II
Building.

                   50.14.   Rentable Area of the Premises: As set forth in
Article 1.1 hereof.

                   50.15.   Tenant: Each and every person hereinabove named as
Tenant on page 1 of this Lease and such persons' respective heirs, personal
representatives, successors and assigns, subject to the provisions of Article
14.7.

                   50.16.   Tenant's Proportionate Share:

                   50.16.1. As to the Centerpointe I Building, Tenant's
Proportionate Share shall be 100% ("Tenant's Centerpointe I Proportionate
Share").

                   50.16.2. As to the Centerpointe II Building, Tenant's
Proportionate Share shall be 18.85% ("Tenant's Centerpointe II Proportionate
Share"), which is derived by dividing the Rentable Area of the Centerpointe II
Premises by 203,630, which is the Rentable Area of the Centerpointe II Building.

         51.       Delivery for Examination. DELIVERY OF THE LEASE TO TENANT
SHALL NOT BIND LANDLORD IN ANY MANNER, AND NO LEASE OR OBLIGATIONS OF LANDLORD
OR TENANT SHALL ARISE UNTIL THIS INSTRUMENT IS SIGNED BY BOTH LANDLORD AND
TENANT AND DELIVERY IS MADE TO EACH.

         52.       Environmental Matters.

                   52.1.    Compliance with Law.  For purposes of this Article
52, Landlord and Tenant shall each be referred to as the "Responsible Party"
with regard to their respective "Control Areas". Tenant's "Control Area" shall
be the Centerpointe I Building (but does not include the Core Elements of the
Centerpointe I Building), and the portion of the Premises in the Centerpointe II
Building, (but does not include the Core Elements within the Centerpointe II
Building that fall within the Centerpointe II Premises) while Landlord's
"Control Area" shall be the Property, exclusive of (i) the Centerpointe I
Building (but including the "Core Elements" of the Centerpointe I Building), and
(ii) the portion of the Premises in the Centerpointe II Building (but including
the Core Elements within the Centerpointe II Building that fall within the
Premises). Each Responsible Party shall conduct, and cause to be conducted, all
operations and activity at its Control Area in compliance with, and shall in all
other respects applicable to such Control Area comply with, all applicable
present and future federal, state, municipal and other governmental statutes,
ordinances, regulations, orders, directives and other requirements, and all
present and


                                       44



future requirements of common law, concerning the environment (hereinafter
collectively called "Environmental Statutes") including, without limitation, (i)
those relating to the generation, use, handling, treatment, storage,
transportation, release, emission, disposal, remediation or presence of any
material, substance, liquid, effluent or product, including, without limitation,
hazardous substances, hazardous waste or hazardous materials, (ii) those
concerning conditions at, below or above the surface of the ground and (iii)
those concerning conditions in, at or outside buildings. In addition, Landlord's
compliance obligation shall extend to matters existing at the Property
(including Tenant's Control Area) prior to the date hereof.

                   52.2.    Permits.  Each Responsible Party, in a timely
manner, with respect to its Control Area, shall obtain and maintain in full
force and effect all permits, licenses and approvals, and shall make and file
all notifications and registrations as required by Environmental Statutes, and
shall at all times comply with the terms and conditions of any such permits,
licenses, approvals, notifications and registrations.

                   52.3.    Documents.  Each Responsible Party shall provide to
the other party copies of the following, forthwith after each shall have been
submitted, prepared or received by the Responsible Party or any occupant of its
Control Area: (i) all applications and associated materials submitted to any
governmental agency relating to any Environmental Statute; (ii) all
notifications, registrations, reports and other documents, and supporting
information, prepared, submitted or maintained in connection with any
Environmental Statute; (iii) all permits, licenses, approvals, and amendments or
modifications thereof, obtained under any Environmental Statute; and (iv) any
correspondence, notice of violation, summons, order, complaint, or other
document received by such Responsible Party or any occupant of its Control Area
pertaining to compliance with or liability under any Environmental Statute.

                   52.4.    Operations.  Neither Responsible Party shall cause
or suffer or permit to occur in, on or under its Control Area any generation,
use, manufacturing, refining, transportation, emission, release, treatment,
storage, disposal, presence or handling of hazardous substances, hazardous
wastes or hazardous materials (as such terms are now or hereafter defined under
any Environmental Statute) or any other material, substance, liquid, effluent or
product now or hereafter regulated by any Environmental Statute (all of the
foregoing herein collectively called "Hazardous Substances"), except that
construction materials (other than asbestos or polychlorinated biphenyls),
office equipment, fuel and similar products (if contained in vehicles) and
cleaning solutions, and other maintenance materials that are or contain
Hazardous Substances may be used, generated, handled or stored in the Control
Area, provided such is incident to and reasonably necessary for the operation
of, maintenance of or conduct of business in the Control Area and is in
compliance with all Environmental Statutes and all other applicable governmental
requirements. Should any release of any Hazardous Substance occur at a Control
Area, the Responsible Party shall immediately contain, remove and dispose of,
from the Control Area such Hazardous Substances, and any material that was
contaminated by the release and to remedy and mitigate all threats to human
health or the environment relating to such release. When conducting any such
measures the Responsible Party shall comply with all Environmental Statutes.


                                       45



                   52.5.    Indemnification.  Each Responsible Party hereby
agrees to indemnify and to hold harmless the other party hereto of, from and
against any and all expense, loss or liability suffered by the other party
hereto by reason of the Responsible Party's breach of any of the provisions of
this Article, including, but not limited to, (i) any and all expenses that the
indemnified party may incur in complying with any Environmental Statutes, (ii)
any and all costs that the indemnified party may incur in studying, assessing,
containing removing, remedying, mitigating, or otherwise responding to, the
unlawful release of any Hazardous Substance or waste at or from the other
party's Control Area, (iii) any and all costs for which the indemnified party
may be liable to any governmental agency for studying, assessing, containing,
removing, remedying, mitigating, or otherwise responding to, the unlawful
release of a Hazardous Substance or waste at or from the other party's Control
Area, (iv) any and all fines or penalties assessed, or threatened to be
assessed, upon the indemnified party by reason of a failure of the indemnifying
party to comply with any obligations, covenants or conditions set forth in this
Article, and (v) any and all legal fees and costs incurred by the indemnified
party in connection with any of the foregoing.

                   52.6.    General Compliance.  The provisions of this Article
52 shall not be construed as limiting in any respect the covenants and
obligations of either party hereunder. All covenants, obligations and
liabilities of Landlord and Tenant under this Article 52 shall survive the
expiration or other termination of this Lease.

         53.       Tenant's Remedies.

                   53.1.    If Landlord shall be in default in the performance
of any of its duties or obligations hereunder for fifteen (15) consecutive days
after written notice from Tenant (unless such default is not susceptible of cure
within fifteen (15) days in which event Landlord shall have failed to commence
curing such default within such fifteen (15) day period and diligently
prosecuted such cure until completion), and as a result thereof all or a
substantial portion of any floor is rendered untenantable, inaccessible,
incapable of use, or Tenant's use or enjoyment thereof is materially and
adversely affected, in addition to any other rights Tenant may have in law or
equity, Tenant may but shall not be obligated to cure such default on behalf of
Landlord. Landlord shall reimburse Tenant upon demand for all reasonable
out-of-pocket costs incurred by Tenant in curing such default, including,
without limitation, reasonable attorneys' fees and other legal expenses,
together with interest thereon at the Lease Interest Rate. Notwithstanding the
foregoing, Tenant shall not have any right in exercising its remedies under the
preceding sentence to make any repairs or modifications to areas outside the
Premises or to Building systems except those within and solely affecting the
Premises or those required to maintain direct access to the Premises or provide
services directly to the Premises (in any case in a manner which does not
materially adversely affect the Buildings or other tenants in the Centerpointe
II Building), or to provide any services for the benefit of any occupants of the
Buildings other than Tenant, or to retain any contractors or subcontractors to
perform such services which are not responsible contractors and subcontractors.
Tenant shall give written notice to Landlord prior to retaining any such
contractors or subcontractors of the identity of such contractors and
subcontractors.


                                       46



                   53.2.    If the cure provided for under Article 53.1 above
involves a payment by Tenant for Landlord's account, then Tenant may set off the
amount of such payment (and the interest provided for in Article 53.1 above)
against any Rent payable by Tenant hereunder except for payments of Base Rent,
unless (a) Landlord's default is a failure to pay any portion of the Concession
Fund when the same is due, in which event Tenant shall have a right of set off
as against Base Rent and Additional Rent in the amount of any portion of the
Concession Fund that was not paid when due, together with interest at the Lease
Interest Rate from the due date until the date of set off, or (b) the set off
right arises in the last year of the Term or in the last year of any Renewal
Period, in which event Tenant shall have a right of set off against Base Rent
and Additional Rent. Notwithstanding anything else herein to the contrary,
however, in the event Landlord disputes that its has the obligation to reimburse
Tenant as aforesaid, Tenant shall not have any right of set off against the
amount thereof against Rent until such time that a court of competent
jurisdiction has entered a judgment which provides that Landlord was in fact
obligated to make such payment or Landlord is determined to have had such
obligation pursuant to the arbitration provisions set forth in Article 65 of
this Lease. The survival of Tenant's set off rights, if any, in the event of a
foreclosure or other enforcement of a mortgage, deed of trust or ground lease
shall be governed by Article 58 below.

         54.       Extension Option.

                   54.1.    So long as Tenant is not in default under this
Lease, Tenant shall have an option to extend the Term of this Lease for two (2)
additional periods of five (5) years each (each a "Renewal Period"). The option
for each such additional 5-year Renewal Period term may be exercised by Tenant
only by written notice (the "Extension Exercise Notice") given to Landlord not
later than the date which is at least fifteen (15) months prior to the
expiration of the Term, in the case of the first 5-year option, and at least
fifteen (15) months prior to the expiration of the first Renewal Period (each an
"Option Exercise Date"), in the case of the second Renewal Period. In the event
that Tenant exercises the option to extend the Term in accordance with the
provisions hereof, the Term shall be extended accordingly. Tenant's extension
option for the first Renewal Period shall be for a minimum of fifty percent
(50%) of the Rentable Area of the Centerpointe I Building in a contiguous block
of space and shall be for no less than one-half of any particular floor.
Tenant's extension option for the second Renewal Period shall be for one hundred
percent (100%) of the space for which Tenant exercised the extension option
during the first Renewal Period. Upon the commencement of each Renewal Period,
Landlord shall grant to Tenant a reasonable refurbishment allowance in such
amount as may be mutually agreed to by Landlord and Tenant, which amount shall
be agreed to in conjunction with, and as a component of, the determination of
"Market Rental Value", as described below. Except as stated below in this
Article, all of the terms and conditions of this Lease in effect immediately
prior to the respective Renewal Period shall equally pertain in all respects to
the respective Renewal Period. All references in this Lease to the Term of this
Lease shall be construed to include the applicable Renewal Period, unless the
context clearly indicates that another meaning is intended. Tenant shall not
have the right to exercise the extension option for the second Renewal Period
unless Tenant had previously exercised the extension option for the first
Renewal Period.


                                       47



                   54.2.    Annual Base Rent during the first Renewal Period
shall be the greater of (i) ninety percent (90%) of the Market Rental Value of
the Premises (as defined and determined below) for that period or (ii) the
then-current rate of Base Rent, net of Base Year Operating Expenses and Base
Year Real Estate Taxes; provided, however, that if the then-current Base Rent,
net of Base Year Operating Expenses and Base Year Real Estate Taxes is greater
than 100% of Market Rental Value, the annual Base Rent shall be 100% of Market
Rental Value. Annual Base Rent for the second Renewal Period shall be one
hundred percent (100%) of the Market Rental Value of the Premises. The
determination of Market Rental Value shall account for the fact that Base Year
operating Expenses and Base Year Real Estate Taxes for each Renewal Period shall
be the Operating Expenses and Real Estate Taxes incurred by Landlord during the
calendar year in which the applicable Renewal Period commences.

                   54.3.    "Market Rental Value" of the Premises for the
Renewal Periods shall be determined by Landlord and Tenant not later than thirty
(30) days after Landlord's receipt of the respective Extension Exercise Notice
("Negotiation Period"). if Landlord and Tenant cannot agree as to Market Rental
Value of the Premises prior to the end of the Negotiation Period, then Tenant
may deliver written notice to Landlord within ten (10) days after the expiration
of the Negotiation Period rescinding Tenant's Extension Exercise Notice, in
which event this Lease shall expire upon the last day of the then-current Term.
If Tenant does not deliver such rescission notice within ten (10) days after the
expiration of the Negotiation Period, then Market Rental Value shall be
determined as follows:

                   54.3.1.  Landlord and Tenant shall each, within fifteen (15)
days after the expiration of the Negotiation Period, select a broker, each of
whom shall be a Virginia-licensed real estate broker with at least ten (10)
years experience in the Fairfax/Fair Oaks office market, who shall determine the
Market Value Rental. The brokers shall be instructed to submit their written
determinations of the Market Rental Value of the Premises to Landlord and Tenant
within thirty (30) days after their appointment. In the event that higher of the
two determinations exceeds the lower of the two determinations by less than five
percent (5%), the Market Rental Value shall be the average of such
determinations. If the higher of the two determinations exceeds the lower of the
two determinations by five percent (5%) or more, the brokers shall, within ten
(10) days, appoint a third broker with similar qualifications to make such
determination of the Market Rental Value in accordance with the foregoing
limitations. In the event that the two brokers cannot agree as to the selection
of the third broker, either party may request that the President of the
Washington Area Commercial Brokers Council appoint the third broker. The third
broker shall be instructed to complete the appraisal procedure and to submit a
written determination of the Market Rental Value to Landlord and Tenant within
thirty (30) days after such broker's appointment. The rental rate that shall be
binding upon Landlord and Tenant as the Market Rental Value shall be the mean of
the two closest determinations; provided, however, that (i) if any determination
is agreed upon by any two of the brokers, then Market Rental Value shall equal
such agreed-upon determination, and (ii) if any determination is equidistant
from the other two determinations, then Market Rental Value shall equal such
middle determination. Landlord and Tenant shall each bear the costs of their
respective brokers. The expenses of the third broker shall be borne one-half
(1/2) by Landlord and one-half (1/2) by Tenant.


                                       48



                   54.3.2.  For purposes of this Article, the term "Market
Rental Value" means the fair market rental rate per square foot of the Rentable
Area of the Premises that would be agreed upon between a landlord and a tenant
of similar creditworthiness entering into a new lease in comparable buildings
(with structured or below-grade parking amenities) of comparable age as the
Buildings, assuming the following: (A) the landlord and tenant are typically
motivated; (B) the landlord and tenant are well informed and well advised and
each is acting in what it considers its own best interests; (C) in the event the
Premises have been destroyed or damaged by fire or other casualty, they have
been fully restored; (D) the Premises are to be let with vacant possession and
subject to the provisions of this Lease for a term commensurate with the
respective Renewal Period. Market Rental Value shall take into account market
rents then being charged for leases of comparable square footage and comparable
space in other similar office buildings in comparable locations, rent escalation
provisions then prevailing, rental abatements, build-out allowances and other
concessions then customarily granted, any savings in brokerage commissions by
Landlord, and other terms customarily agreed to in market leases entered into at
such times.

         55.       Signage.

         Tenant shall have the right to install two illuminated signs on the top
of the Centerpointe I Building identifying Tenant's corporate name or logo. The
signs must be of design, material, size, color, location and construction
methods acceptable and approved by Landlord prior to installation, which
approval shall not be unreasonably withheld, delayed or conditioned. In
addition, the signs shall be built and installed in accordance with all
applicable local county and state codes. Subject to the signage rights of
existing tenants (including how those prior rights impact on the total allowable
signage for the Property), Tenant shall have the right to install a monument
sign at the approach to the Centerpointe I Building so long as such sign
complies with all applicable local, county and state codes, and is of a design,
character and at a location reasonably satisfactory to Landlord. The signs shall
be provided and installed by Tenant as part of the Concession Fund and the signs
shall be removed and the Buildings restored to their original condition at
Tenant's expense at the end of the Term. So long as Tenant occupies more
Rentable Area in the Buildings than any other tenant, Landlord shall grant no
further signage rights to other tenants. At such time as (i) the rights of
Quality Systems, Inc. expire in and to the Centerpointe II Building, and (ii) in
the event Tenant is leasing at least twenty-five percent (25%) of the Rentable
Area of the Centerpointe II Building, and (iii) there is no contiguous space
leased to a single tenant or contiguous empty space in the Centerpointe II
Building containing a Rentable Area which is greater than the Rentable Area
leased by Tenant in the Centerpointe II Building, then Tenant shall have the
right to install one illuminated sign on the top of the Centerpointe II Building
identifying Tenant's corporate name or logo. Such sign shall be subject to the
same requirements as are set forth above with respect to the signs on the
Centerpointe I Building.

         56.       Storage Space.

         Tenant shall have the right, at its sole cost and expense, to convert
up to approximately 3,000 square feet of Tenant's garage parking area (described
in Article 60 below) to a storage area provided that such conversion is in
accordance with law and is in a location and design acceptable to Landlord,
which approval shall not be unreasonably withheld, delayed or conditioned. Any


                                       49



parking converted to storage shall directly reduce Tenant's parking allocation,
as described in Article 60. All storage improvements shall be removed and the
garage restored to its original condition at Tenant's expense, at the end of the
Term.

         57.       Food Service In Centerpointe II Building. Landlord agrees
that so long as Tenant does not operate its own cafeteria in either of the
Buildings, Landlord shall not lease the portion of the first floor of the
Centerpointe II Building which is presently leased to Centerpointe Cafe for use
other than as a deli-type food service operation comparable to that offered by
Centerpointe Cafe. Tenant acknowledges that Landlord shall have the right to
change the location of the food service operation to any other portion of the
first floor of the Centerpointe II Building (provided that such new space shall
provide for seating for at least 85 patrons), in which event the negative
covenant described in the first sentence of this Article shall apply only to
such space and that Landlord is free to change the identity of the tenant of
such food service operation from time to time during the Term of this Lease.

         58.       Non-Disturbance. As to each Overlessor, deed of trust
trustee, mortgagee or holder of any other interest to which this Lease shall
hereafter become subordinate pursuant to Article 35 or Article 36 (each a
"Senior Holder"), such subordination is subject to the express condition that so
long as Tenant is not in default in its obligations hereunder beyond applicable
grace periods, (a) Tenant will not be made a party in any action or proceeding
by such Senior Holder to recover possession of the Property and/or the Premises,
or to any trustee's or sheriff's sale of the Property or to foreclose any
mortgage, (b) Tenant's possession shall not be disturbed by such Senior Holder,
and (c) this Lease shall not be cancelled or terminated by such Senior Holder
and shall continue in full force and effect upon such foreclosure or recovery of
possession as a direct lease between Tenant and the person or entity acquiring
the interest of Landlord, or between Tenant and the Overlessor, as the case may
be, upon all the terms, covenants, conditions and agreements set forth in this
Lease, provided in each case that, unless the Senior Holder is the General
Electric Pension Trust, the trustees or any subsidiary thereof, neither such
Senior Holder nor any person or entity acquiring title to the Buildings as a
result of foreclosure or trustee's sale nor any successor or assign of either of
the foregoing shall be (i) bound by or liable for any payment of Rent which may
have been made more than thirty (30) days before the due date of such
installment, (ii) subject to any defense or offset which Tenant may have to the
payment of Rent or other performance under this Lease, unless a Senior Holder
that institutes a foreclosure or other conveyance of title to a Building or
Buildings has been notified of Tenant's claim of a set off right, and, if the
set off rights are determined pursuant to a court action or arbitration, has
been given the opportunity to appear in, an action in which Tenant is awarded a
set off right pursuant to Article 53.2 above, in which event Tenant's right of
set off shall be limited as against such Senior Holder or any party acquiring
such title to 75% of any Monthly Installments of Additional Rent payable
thereunder from time to time from and after the date on which such Senior Holder
or other party acquires title to a Building or Buildings, (iii) bound by any
amendment or modification to this Lease made without the consent of such Senior
Holder, (iv) liable for any monies owing by Landlord or on deposit with Landlord
to the credit of Tenant, which such Senior Holder shall not have received,
except as aforesaid, or (v) bound by or liable for any act or omission of any
prior Landlord, and Tenant shall not have any right to set off (except as
provided in clause (ii) above) or assert against such Senior Holder or other
person or entity any claim or damages arising therefrom. The provisions of this


                                       50



Article 58 shall be self-operative and no further instrument of subordination or
attornment shall be required to be provided by any Senior Holder or by Tenant.
Tenant agrees, however, whenever requested to do so upon reasonable notice, to
execute such instruments confirmatory of the provisions of this Article 58 as
Landlord or any Senior Holder requesting the same may reasonably require.

         59.       Exercise Room. Landlord shall provide an allowance of $35,000
for Tenant's purchase of exercise equipment for use in the fitness center which
Tenant intends to construct in the Centerpointe I Building. The foregoing
equipment allowance shall be in addition to the Concession Fund. The fitness
center shall otherwise be constructed by Tenant at Tenant's sole cost and
expense.

         60.       Parking. Tenant shall have the right to park up to 3.6
automobiles per 1,000 rentable square feet of the Premises free of charge to
Tenant throughout the Term (including any renewal terms), subject to
readjustment pursuant to Article 56 above. Tenant's total parking allotment
shall initially be eight hundred seventy-one (871) spaces (which spaces shall be
unassigned for the portion of the garage beneath the Centerpointe II Building),
comprised of seven hundred fourteen (714) spaces in the garage and one hundred
fifty-seven (157) spaces on the surface lot. Landlord shall designate within the
garage that portion of the garage for use by tenants of each of the respective
Buildings. Tenant's garage parking shall include the entire portion of the
garage designated by Landlord for the use of the Centerpointe I Building (which
portion shall be below the Centerpointe I Building) provided that Tenant's usage
shall not restrict access and use of the parking areas for the Centerpointe II
Building.

         61.       Right of First Offer.

                   61.1.    At any time that there remains at least four (4)
years in the Term, including during any exercised Renewal Periods, (provided,
however, that the rights set forth in this Article 61 during a Renewal Period
shall only be applicable if Tenant is occupying eighty percent (80%) or more of
the Rentable Area of the Centerpointe I Building), and provided Tenant is not in
default of any of the terms and conditions in this Lease, Tenant shall have the
rights of first offer set forth in this Article with respect to any space in the
Centerpointe II Building that becomes available following (or in anticipation
of) the vacation of such space by any tenant, provided that the space is not as
of the date of this Lease under any previous options or rights of first offer or
first negotiations to any other tenant (or its assignee or sublessee) of the
Centerpointe II Building (the "First Offer Space"). First Offer Space shall not
include any space which was not previously leased to and occupied by another
tenant. Gin the event that Landlord shall propose to actively market or lease
any First Offer Space to prospective tenants' then Landlord shall first give
written notice (the "Offer Notice") to Tenant notifying Tenant of such intention
and designating the First Offer Space which Landlord intends to so market or
lease and specifying in good faith the Base Rent, Additional Rent, escalations,
tenant concessions and other terms and the date on which Landlord would require
Tenant or the prospective tenant to occupy such First offer Space (each such
date shall herein be defined as a "Scheduled Commencement Date") Upon the giving
of an Offer Notice by Landlord, Tenant shall thereupon have an option (a "Right
of First Offer"), exercisable by notice (an "Acceptance Notice") given to
Landlord not later than ten (10) business


                                       51



days after the receipt of the Offer Notice, to lease the designated First Offer
Space on the terms and conditions specified below in this Article. If the First
Offer Space shall be for a term which is not coterminus with the Term of this
Lease, Landlord's Offer Notice shall also include the terms and conditions upon
which Landlord would lease the First Offer Space for a term that is coterminus
with the Term, and Tenant shall elect in its Acceptance Notice whether Tenant
shall lease the First Offer Space for a coterminus term upon such terms and
conditions or for the term that Landlord had otherwise been marketing for the
First Offer Space. In the event Tenant does not exercise its option as aforesaid
for any First Offer Space as to which Tenant receives an Offer Notice from
Landlord, then Landlord shall have the right to enter into a lease with respect
to such designated First Offer Space (on terms substantially similar to, and at
a net effective base rental which is no less than 95% of, the terms of the Offer
Notice) with another tenant during the period which is twelve (12) months after
the date of Landlord's Offer Notice. If Landlord enters into a lease with
another tenant for First Offer Space as aforesaid, at the end of the term of any
such lease, Tenant's rights of first offer shall be reinstated for the remainder
of the Term of this Lease as to such space, subject to the terms and conditions
herein stated.

                   61.2.    In the event that Tenant shall exercise its Right of
First offer with respect to any First Offer Space, all of the terms and
conditions of this Lease applicable to the Premises generally, shall apply to
such First Offer Space, except that Base Rent, Additional Rent, renewal options,
escalations, tenant concessions and other economic terms and any other terms set
forth in the Offer Notice shall control if inconsistent with this Lease (or if
not addressed in this Lease), and except as otherwise set forth below in this
Article. Landlord and Tenant shall execute a lease addendum within twenty (20)
days after the date of the Acceptance Notice to memorialize the terms of the
Offer Notice. First Offer Space shall be delivered to Tenant in its then "as-is"
condition and state or repair, unless otherwise specified in the Offer Notice.

                   61.3.    The Scheduled Commencement Date for First Offer
Space as to which Tenant shall have given an Acceptance Notice ("Accepted First
Offer Space") and the dates upon which Rent shall become due shall be specified
by Landlord in the Offer Notice. If Landlord shall fail to deliver timely
possession of such Accepted First Offer Space for any reason beyond Landlord's
control, Landlord shall not be subject to any liability to Tenant, provided,
however, that Landlord shall use reasonable efforts to evict any holdover tenant
and the date upon which Rent shall be payable shall be equitably adjusted.

                   61.4.    The Term of this Lease shall commence as to each
Accepted First Offer Space on such date, which for purposes of this Article
shall be a "Subsequent Lease Commencement Date" for such Accepted First Offer
Space, as shall be the date (the "Availability Date") Landlord makes such
Accepted First Offer Space available for the commencement of Tenant Work. On the
Subsequent Lease Commencement Date for such Accepted First Offer Space, such
First Offer Space shall become part of the Premises. This Lease shall terminate
as to Accepted First Offer Space upon the expiration of the Term, if the term
for such First Offer Space is co-terminus with the Term, or on the date
otherwise specified in the Offer Notice and elected by Tenant in the Acceptance
Notice.


                                       52



                   61.5.    From and after the Subsequent Rent Commencement Date
for Accepted First Offer Space, the "Tenant's Centerpointe II Proportionate
Share" shall be increased by the percentage which is derived by dividing the
rentable square footage of such Accepted First offer Space by 203,630.

         62.       Expansion Space.

                   62.1.    So long as Tenant is not in default under the terms
of this Lease, Tenant shall have the option to lease the approximately 9,062
rentable square feet of the sixth (6th) floor and the approximately 9,469
rentable square feet of the tenth (10th) floor in the Centerpointe II Building
which are not presently leased to other tenants ("Expansion Space"), provided
that Tenant exercises its option to lease either or both partial floors by
written notice delivered to Landlord ("Expansion Notice") on or before March 31,
1993, which notice shall advise Landlord of the date that Tenant shall occupy
the Expansion Space, which date shall be no later than March 1, 1994. Landlord
shall make available the Expansion Space to Tenant for Tenant Work within five
(5) days after Landlord's receipt of the Expansion Notice.

                   62.2.    If Tenant delivers to Landlord its Expansion Notice
at any time on or before March 31, 1993, all of the terms and conditions of this
Lease applicable to the Premises shall apply to such Expansion Space, except as
set forth below in this Article. Expansion Space shall be delivered to Tenant in
its then "as-is" condition and state of repair, but the Concession Fund shall be
increased pro rata based on the square footage of the Expansion Space.

                   62.3.    The Term of this Lease shall commence as to such
Expansion Space on such date, which for purposes of this Lease shall be the
"Expansion Space Lease Commencement Date," as shall be the date Tenant or anyone
claiming under or through Tenant enters such Expansion Space to commence actual
construction of the Tenant Work.

                   62.4.    Tenant's obligation to pay Rent for the Expansion
Space shall commence on March 1, 1994 ("Expansion Space Rent Commencement
Date"). If Tenant occupies the Expansion Space for the Permitted Use prior to
the Expansion Space Rent Commencement Date, Tenant shall pay to Landlord for the
period between the date of such occupancy and the Expansion Space Rent
Commencement Date, an amount equal to Five Dollars ($5.00) per rentable square
foot per annum, in equal monthly installments, in advance, as Additional Rent
hereunder. All other obligations of Tenant pertaining to the Expansion Space
under this Lease shall commence on the Expansion Space Lease Commencement Date.

                   62.5.    Unless Tenant exercises its option to lease both of
the partial floors that comprise the Expansion Space, as provided in Article
62.1 above, Landlord agrees, (i) as to one of the two partial floors, to be
selected by Landlord, if neither partial floor is so leased by Tenant, or (ii)
as to the remaining partial floor, if one of the partial floors is so leased by
Tenant (the applicable floor in item (i) or (ii) above is herein defined as
"Five Year Space"), that Landlord will not enter into any lease for the Five
Year Space for a term that exceeds five (5) years, and following the expiration
of the term of such lease for the Five Year Space, Tenant shall have the option
to lease the Five Year Space, to be exercised by the delivery of a notice to
Landlord within thirty (30) days after Landlord provides Tenant with written
notice as to the availability of the Five


                                       53



Year Space, provided that the Base Rent payable with respect to the Five Year
Space shall be at the "Market Rental Value," as defined in, and determined
under, Article 54.3 above. Any renewal rights granted to a tenant of the Five
Year Space shall be subordinate to Tenant's option as aforesaid.

                   62.6.    After the Expansion Space Rent Commencement Date
with respect to the Expansion Space, Tenant's Centerpointe II Proportionate
Share shall be increased by an amount equal to the percentage derived by
dividing the rentable square footage of the Expansion Space by 203,630.

         63.       Measurement of Premises.  Intentionally Omitted

         64.       Tenant's Affiliation Representation. Tenant represents and
warrants that (i) it does not directly or indirectly control the General
Electric Company and is not directly or indirectly controlled by or under common
control with the General Electric Company; (ii) neither the Tenant nor any
principal of the Tenant is an officer, director or employee of the General
Electric Company or any subsidiary of any affiliated company of the General
Electric Company; and (iii) it is not a partnership in which the General
Electric Company or any subsidiary of any affiliated company of the General
Electric Company is a ten percent (10%) or more (directly or indirectly, in
capital or profits) partner.

         65.       Arbitration

                            (a)      If any controversy shall arise between the
parties with respect to the matters stated in this Lease to be resolved by
arbitration and that dispute shall not be resolved by the parties within ten
(10) days after either of the parties shall notify the other of its desire to
arbitrate the dispute, then the dispute shall be settled by arbitration, as
hereinafter provided, and judgment upon the award shall be entered in any court
having jurisdiction. The arbitrators shall have no power to change any
provisions of this Lease in any respect, and the jurisdiction of the arbitrators
is expressly limited accordingly. Neither party shall interrupt the progress of
its respective area of performance under this Lease pending the determination in
the arbitration proceeding.

                            (b)      The party desiring such arbitration shall
give written notice to that effect to the other party and shall in such notice
appoint a disinterested person in the Northern Virginia area of recognized
competence and experience in the field which is the subject matter of the
dispute as one of the arbitrators. Within fifteen (15) days thereafter, the
other party shall, by written notice to the original party, appoint a second
disinterested person in the Northern Virginia area of recognized competence and
having at least ten (10) years experience in such field as an arbitrator. The
arbitrators thus appointed shall appoint a third disinterested person in the
Northern Virginia area of recognized competence in such field, and such three
arbitrators shall, as promptly as possible, determine such matter, provided,
however, that (i) if the second arbitrator shall not have been appointed as
aforesaid, the first arbitrator shall proceed on ten (10) days notice to the
parties to determine such matter; and (ii) if the two arbitrators appointed by
the parties shall be unable to agree, within fifteen (15) days after the
appointment of the second arbitrator, upon the appoint of a third arbitrator,
they shall give written notice of such failure to agree to the parties,


                                       54



and, if the parties fail to agree upon the selection of such third arbitrator
within fifteen (15) days after the arbitrators appointed by the parties give
notice as aforesaid, then within ten (10) days thereafter either of the parties
upon written notice to the other party hereto may request such appointment by
the American Arbitration Association (or any organization successor thereto), or
in its absence, refusal, failure or inability to act, may apply for such
appointment to a Court of competent jurisdiction.

                            (c)      The arbitration shall be conducted in
accordance with the rules of the American Arbitration Association (or its
successor) and the decision of a majority of the arbitrators (or sole
arbitrator, as the case may be) shall be binding, final and conclusive on the
parties and judgment thereon may be entered in any court having jurisdiction
thereof. Landlord and Tenant shall be entitled to present evidence and arguments
to the arbitrators. If a majority of the arbitrators (or sole arbitrator, as the
case may be) believe that expert advice would materially assist them in the
resolution of the matter in dispute, they may retain one or more qualified
persons, including, but not limited to, legal counsel, architects or engineers,
to provide such expert advice. The fees of the arbitrators and the expenses
incident to the proceedings shall be borne equally between Landlord and Tenant.
The fees of respective counsel engaged by the parties, and the fees of expert
witnesses and other witnesses called by the parties, shall be paid by the party
which loses in the proceedings The arbitrators shall give written notice to the
parties stating their determination, and shall furnish a copy of such
determination signed by them to each party.

         IN WITNESS WHEREOF, and intending to be legally bound hereby, the
parties hereto have executed this Agreement of Lease on the date first set forth
herein.

                                          Landlord:
                                          JOSHUA REALTY CORPORATION, a Delaware
                                          corporation

                                          By:      /s/ Steven D. Burton
                                                   ------------------------
                                          Steven D. Burton,
                                          Vice President

                                          Tenant:
                                          AMERICAN MANAGEMENT SYSTEMS, INC,
                                          a Delaware corporation

                                          By:      /s/ Frank A. Nicolai   (Seal)
                                                   -----------------------


[THE FOLLOWING PAGES OF THE ORIGINAL DOCUMENT INCLUDED AS EXHIBITS A-1 AND A-2
FLOOR PLANS OF THE PREMISES.]


                                       55


                                 EXHIBIT "B"

                   Landlord's Base Building Modifications

         The following items are to be the sole responsibility of the Landlord.
The items will be completed in accordance with the dates indicated below:

         1.      Landlord will provide electrical sub-meters for first floor
tenant space in the Centerpointe I Building by December 1, 1992 and the third
and the fourth floors in the Centerpointe II Building by August 1, 1993.

         2.      The base Building core shells were constructed in accordance
with 1984 BOCA Codes at which time the building met all applicable codes.
Landlord will make any modifications allowable per code to bring the Building
up to the 1990 BOCA Code by December 1, 1992.

         3.      Landlord will provide roll-down doors at garage entry/exits
with card readers for security purposes by December 1, 1992.

         4.      By December 1, 1992, Landlord will provide an awning over the
loading dock area from the exterior Building doors to compactor area for the
Centerpointe I Building.  Additionally, by December 1, 1992 a ramp will be
constructed in place of the stairs adjacent to the dock for the Centerpointe I
Building.  The final design, material, color and location shall be subject to
all County codes, as well as Tenant's review.

         5.      Landlord will reimburse Tenant for the costs incurred in
connection with the removal of all existing data/telecommunications wiring from
previous tenants.  Such reimbursement shall be in addition to the Concession
Fund.

         6.      Landlord will diligently pursue alternatives to provide easier
walking access to Fair Oaks Mall.  Landlord's total cost for design,
engineering and construction shall not exceed $25,000.  Any in-house costs
associated with the approval process shall be at the Landlord's expense.

         7.      Landlord has negotiated with the County for the right of
Tenant to occupy, on a rent-free basis, a maximum of 2,000 square feet in the
Centerpointe I Building in a location reasonably acceptable to the County, for
use as a construction management office.  Tenant agrees to indemnify, defend
and hold Landlord harmless from and against any loss arising from Tenant's use
of such space.

         8.      Landlord will provide Tenant with transformers to accommodate
4 watts per square foot demand load at 120 volts for tenant power on a floor by
floor basis on the respective Lease Commencement Date and Subsequent Lease
Commencement Date for each floor.





                                     B-1

         9.      Based on a maximum occupancy of one hundred ten (110) people
on a typical full office floor, the Landlord will provide 2,200 cubic feet per
minute (CFM) of outside air per floor.  The actual available outside air
volume, per floor, will be confirmed by an AABC or NEBB certified air balance
report.  All costs associated with providing certified air balance report shall
be borne by Landlord.  Should the actual available outside air volume on a
typical office floor be less than 1,980 CFM of outside air, the Landlord, at
its expense, will increase outside air volume to a minimum 2,200 CFM, per
floor, by May 1, 1993.

         10.     Landlord will provide the necessary improvements to reduce the
average noise levels in office areas not to exceed NC-35 and areas within 101
of machine rooms not to exceed NC-40.  Tenant will assist Landlord by
attempting to locate non-office uses around mechanical rooms on the respective
Lease Commencement Date and Subsequent Lease Commencement Date for each floor.

         11.     Landlord shall prepare a plan with respect to ADA requirements
for the Buildings by December 15, 1992, which Tenant shall have the right to
review (but not approve), it being acknowledged that Landlord shall in its sole
judgment determine what modifications to the Core Elements may be necessary to
comply with ADA.





                                      B-2

                                  EXHIBIT "C"

                     Tenant Design and Construction Process

         Tenant shall construct the Tenant Work in a good and workmanlike
manner and in compliance with all laws and all requirements of insurance
underwriters rating or insuring the Buildings, the Premises and/or the
Property, and in accordance with the following requirements:

         1.      DESIGN.

                 A.       The plans, specifications and drawings for the Tenant
Work (the "Tenant Plans") shall be prepared by Tenant's architect and
engineers, who shall be licensed and registered in the Commonwealth of
Virginia, shall be sufficient for governmental approval and construction
thereof, and comply with the plans and specifications for the Buildings and
with all applicable laws, ordinances, rules, regulations and other requirements
of all governmental and quasi-governmental authorities having jurisdiction
thereof and all insurance requirements.

                 B.       The Tenant Plans for the Initial Space shall be
delivered to Landlord promptly following the date hereof for Landlord's
approval, and, for Subsequent Space, no later than the same time such Plans are
submitted to Tenant's General Contractor (as defined in Paragraph 2 below) for
pricing of Tenant Work on such Subsequent Space.  Landlord shall not
unreasonably withhold, condition or delay its approval of the Tenant Plans or
any revisions thereto (the Tenant Plans as approved by Landlord are hereinafter
referred to as the "Final Plans") and within five (5) business days of receipt
of the Tenant Plans, Landlord will notify Tenant in writing ("Landlord's Plan
Notice") whether the Tenant Plans have been approved or disapproved, and if
disapproved, Landlord's Plan Notice shall explain in reasonable detail the
deficiencies that resulted in the disapproval.  Following receipt of Landlord's
Plan Notice, Tenant shall submit to Landlord revisions of the Tenant Plans
which correct the deficiencies.  If Landlord shall disapprove the revisions of
the Tenant Plans, Landlord's Revised Plan Notice shall explain in reasonable
detail the deficiencies which resulted in the disapproval.  Following receipt
of Landlord's Revised Plan Notice, Tenant shall submit to Landlord further
revisions to the Tenant Plans which correct the deficiencies.  The procedures
and time periods relating to submitting and resubmitting and approving or
disapproving revisions to the Tenant Plans shall apply to any subsequent
revisions to the Tenant Plans.

                 C.       Tenant shall have the right to make changes from time
to time to the Final Plans (herein called the "Revisions").  All Revisions
which affect structural, or materially affect electrical, plumbing or
mechanical components of the Buildings shall be subject to Landlord's prior
written approval, which approval shall not be unreasonably withheld,
conditioned or delayed.  No approval of Tenant Plans and/or Final Plans shall
in any way be deemed to be an agreement by Landlord that the Tenant Plans, the
Final Plans and/or the Tenant Work comply with any laws, ordinances, rules,
regulations or requirements of any governmental authority having jurisdiction
thereof or any insurance requirements.





                                      C-1

         2.      COSTS.

                 Tenant shall enter into a construction contract ("General
Contract Agreement") for the performance of the Tenant Work with Davis
Construction Company (such firm being hereinafter referred to as the "General
Contractor").  Tenant shall have the right to change the General Contractor
subject to Landlord's prior written consent, which consent shall not be
unreasonably withheld, conditioned or delayed.  Landlord shall have the right
to review the mechanical, electrical and plumbing subcontractors that will
perform any of the Tenant Work, as well as any subcontractors that will perform
any structural work.  Prior to entering into the General Contract Agreement,
Tenant shall submit the same to Landlord for its approval, which approval shall
not be unreasonably withheld, conditioned or delayed.  The General Contractor
Agreement shall not be modified, amended or terminated without obtaining the
prior written consent of Landlord, which consent shall not be unreasonably
withheld, conditioned or delayed.  The General Contract Agreement and each
subcontract shall provide for a ten percent (10%) retainage until the Tenant
Work shall be substantially completed in accordance with the Final Plans.
Provided that Landlord disburses the Concession Fund in accordance with the
terms of Exhibit "D", Tenant shall pay, when due, all amounts owing to the
General Contractor or any other person in connection with the construction
and/or performance of the Tenant Work.  Tenant and the General Contractor shall
be solely responsible for the transportation, safekeeping and storage of
materials and equipment used in the performance of the Tenant Work, for the
removal of waste and debris resulting therefrom to the Buildings' dumpsters and
for any proven damage caused by them during the course of the Tenant Work to
the Buildings or the Property.  Tenant shall not permit any financing
statements or statements to be filed with respect to any of the foregoing
alterations, additions or improvements by Tenant.

         3.      COMPLETION.

                 A.       Tenant shall be solely responsible for the
construction of the Tenant Work.  Tenant and its contractors shall work in
harmony and shall not interfere with Landlord, Landlord's contractors, any
other tenants of the Buildings or such tenants' contractors.

                 B.       All Tenant Work shall be done in accordance with, and
subject to all of the terms and conditions provided in this Exhibit "C".  In
connection therewith, Tenant and/or its contractors shall provide to Landlord,
and shall maintain at all times during the performance of Tenant Work,
Insurance as described in the Insurance Addendum attached hereto as Schedule
"C-1".  Certificates for such insurance shall be furnished to Landlord before
Tenant or its contractors commence to perform Tenant's Work.  Landlord shall
not be liable in any way for any injury, loss or damage that may occur to any
of Tenant's, or Tenant's contractor's decorations, fixtures, installations,
supplies, materials, or equipment unless any such injury, loss or change is due
to Landlord's gross negligence or willful misconduct and is not covered by
insurance which Tenant  is required to carry pursuant to this Exhibit "C"; any
such entry upon the Premises by Tenant and/or its contractors being at their
sole risk.

                 C.       Prior to the final payment under the General Contract
Agreement for the Initial Space, or any segment of the Subsequent Space, Tenant
shall deliver to Landlord a copy of





                                      C-2

the final certificate of occupancy (or a non-residential use permit, if such a
permit is issued in lieu of a certificate of occupancy) for the Initial Space
or the relative segment of the Subsequent Space, together with certificates of
substantial completion by Tenant's architect, Tenant's engineers and by the
General Contractor, all of which shall certify to Landlord that the Tenant Work
has been completed substantially in accordance with the Final Plans and any
changes thereto made in accordance with the terms of this Lease.  Prior to the
final payment under the General Contract Agreement, Tenant shall deliver to
Landlord a reproducible sepia of the "as built" plans and specifications for
the fully completed Tenant Work prepared and certified by Tenant's architect or
the General Contractor.  Without limiting the foregoing, Tenant shall be
responsible for obtaining a certificate of occupancy (or a non-residential use
permit, if such a permit is issued in lieu of a certificate of occupancy) for
the Premises or such other certificate or approval as shall be required in
order for Tenant to legally occupy the Premises and shall promptly deliver a
copy thereof to Landlord.

         4.      TENANT'S REPRESENTATIVES.

                 Tenant hereby constitutes and appoints Dale Moser, Tom Huba
and Mike Mitchell (AMS) and Mike Solomon and Gary Helminski (Cushman &
Wakefield) its representatives (individually a "Tenant Representative" and
collectively the "Tenant Representatives") to deal with Landlord in connection
with the Tenant Work.  Any notices and/or approvals given to or by any one of
the said Representatives shall be binding upon Tenant and Landlord shall be
entitled to rely on notices or approvals delivered by any one of such
Representatives.  Tenant may change the designation of the Tenant
Representatives by notice in writing to Landlord.

         5.      DISBURSEMENT PROVISIONS.

                 Tenant shall, from time to time during the course of
construction of the Tenant Work and following the completion of the
construction by Tenant of the Tenant Work, but not more frequently than once
per month, submit to Landlord an Application for Payment in the form attached
hereto as Exhibit "D" which shall set forth the amount of all costs and
expenses which have been incurred by Tenant to the date of such statement for
Tenant Work (excluding amounts previously reimbursed to Tenant by Landlord
pursuant to previous statements) and for which Tenant is entitled to
reimbursement from the Concession Fund as more particularly set forth in
Article 4.2 of the Lease to which this Exhibit "C" is attached.  Each
Application for Payment shall be accompanied by supporting waivers of liens
from the General Contractor and from each subcontractor to which payments will
be made from advances made pursuant to the Application for Payment.  Provided
that the Concession Fund has not been exhausted and there is no default (which
default shall not require the delivery of any notice or the expiration of any
cure periods for the purpose of relieving Landlord from any obligation to
advance any portion of the Concession Fund in the face of such default,
although Tenant shall otherwise be entitled to applicable notice and cure
periods as a condition precedent to Landlord exercising its remedies under the
Lease) under the Lease, Landlord will cause the approved amount to be paid to
Tenant on the fifth (5th) business day after Landlord's receipt thereof;
provided further that all other conditions set forth in this Exhibit "C" shall
have been satisfied.





                                      C-3

         6.      TENANT SUBMISSIONS.

                 A.       Prior to the commencement of construction in the
Initial Space, and prior to the commencement of construction in any segment of
the Subsequent Space, Tenant shall submit to Landlord a copy of the building
permit or permits required for the construction of the Tenant Work as to such
space.

                 B.       Prior to the final payment under the General Contract
Agreement, Tenant shall deliver to Landlord final lien waivers from the General
Contractor, Tenant's architect and engineers (to the extent they are entitled
to file mechanic's liens with respect to their services) and all
subcontractors, materialmen and suppliers.  Tenant shall use its best efforts
to secure lien waivers as aforesaid.  If Tenant cannot secure any such lien
waiver(s) Tenant agrees to post a bond to clear any such lien if filed of
record.

         7.      OWNERSHIP OF IMPROVEMENTS.

                 Landlord and Tenant hereby agree and acknowledge that,
notwithstanding the fact that Tenant may be contracting for the design and
construction of the Tenant Work, immediately upon its installation in the
Premises, all Tenant Work (including, without limitation, all general office
construction items, all mechanical, plumbing and HVAC equipment, all voice or
data communications wiring, and all raised computer access flooring) shall be
and remain the property of Landlord, and shall not thereafter (except as
otherwise provided in the Lease) be subject to removal by Tenant or in any
other manner be deemed the property of Tenant.

         8.      TENANT'S RIGHTS.

                 In its performance of the Tenant Work, Tenant shall have the
right to take such actions and utilize such facilities as are customarily and
reasonably taken and utilized in the construction of comparable space, subject
to such customary and reasonable restrictions as Landlord may adopt in the
prudent management of the Buildings.  Tenant shall not be charged for the use
of utilities, elevators, loading docks, and similar Building facilities in the
construction of the Tenant Work.  No fees of any manner shall be charged by
Landlord for its review of plans and drawings or any supervision or inspection
of the Tenant Work.  Landlord shall cause any of its contractors working in the
Buildings to work in harmony with Tenant and the General Contractor, and
Landlord shall not knowingly permit any other contractors to interfere with the
performance of the Tenant Work.





                                      C-4

Insurance Addendum
Page 1


                                 EXHIBIT "C-1"
                               INSURANCE ADDENDUM

This Insurance Addendum is a part of the Agreement between Owner and Contractor
dated ____ July 1992.

Notwithstanding anything to the contrary in the Agreement to which this
Addendum is attached, or in any other agreement between Contractor, Owner
and/or Architect, Landlord or their respective subcontractors, agents,
employees or representatives, the parties hereto agree as follows:

         All general liability and umbrella liability insurance coverage
         required herein or in any other agreement between the parties shall be
         written on an "Occurrence Basis".

         Contractor shall at all times during the period in which this Contract
         is in force, provide, maintain and require all subcontractors to
         provide and maintain the following types of insurance protecting the
         interest of Landlord and Owner and Contractor with limits not less
         than those as set forth below:

                 WORKER'S COMPENSATION INSURANCE (WC) to cover statutory limits
                 of the Worker's Compensation Law of the State of Virginia,
                 with Coverage B Employer's Liability coverage in limits not
                 less than $500,000

                 COMMERCIAL GENERAL LIABILITY (GGL) insurance for hazards of
                 (i) Premises Operations, (ii) Elevators and Escalators, (iii)
                 Independent Contractors, (iv) Coverage for explosion,
                 collapse, and underground (X, C, U), (v) Products and
                 Completed Operations coverage, (vi) Contractual Liability on a
                 "Blanket" basis designating all written and oral contracts
                 related to the work, (vii) Personal Injury Liability for
                 groups of offenses A, B, and C (with exclusions pertaining to
                 liability assumed by the insured under contract, and to
                 personal injury sustained by any person as a result of an
                 offense directly or indirectly related to the employment of
                 each person by the named insured deleted), and (viii)
                 Incidental Medical Malpractice coverage.  Such Commercial
                 General Liability Insurance must be endorsed with a Broad Form
                 Property Damage Endorsement (including Complete Operations).

                 The Contractual Liability coverage must be endorsed so that
                 all exclusions relating to explosion, collapse and underground
                 hazards are deleted.  The CGL insurance shall have primary
                 coverage limits not less than following:


Insurance Addendum
Page 2


                 BODILY INJURY LIABILITY/PROPERTY DAMAGE LIABILITY - $1,000,000
                 each occurrence, combined single limit.

                 PERSONAL INJURY LIABILITY - $1,000,000 each person;

AUTOMOBILE LIABILITY INSURANCE (Auto) covering all owned, leased, non-owned and
hired automobiles used in connection with the Work with coverage limits not
less than the following:

                 BODILY INJURY LIABILITY/PROPERTY DAMAGE LIABILITY - $1,000,000
                 each person and each occurrence, combined single limit.

COMPREHENSIVE CATASTROPHE LIABILITY INSURANCE (Umbrella) indemnifying for
ultimate net loss sustained by reason of any liability whether imposed by law,
assumed under contract, or otherwise incurred arising out of:

                 BODILY INJURY, including personal injury, because of bodily
                 injury, including death at any time resulting therefrom,
                 sustained by any person or persons.

                 PROPERTY DAMAGE, for losses due to damages to or destruction
                 of tangible property, including loss of use of such property
                 resulting therefrom.

         The Umbrella insurance shall set forth coverage limits with respect to
         each occurrence, except for the products hazard coverage which shall
         contain aggregate limits for each annual period.  With regard to
         Contractor, the Umbrella insurance shall have coverage limits not less
         than FIVE MILLION DOLLARS AND 00/100 ($5,000,000) for each occurrence
         and in the aggregate as applicable in excess of the amount set forth
         in subparagraphs (WC), (CGL) & (AUTO) above.  For each subcontractor
         employed in conjunction with the Work, the Umbrella insurance shall
         have coverage limits not less than TWO MILLION DOLLARS AND 00/100
         ($2,000,000) for each occurrence and in the aggregate as applicable in
         excess of the amount set forth in subparagraphs (WC), (CGL) & (AUTO)
         above.

         In the event that Contractor or  any subcontractors have or obtain
         insurance coverage in amounts in excess of those listed above, such
         additional insurance coverage shall also insure to the benefit of the
         Landlord and Owner.

Contractor shall be liable to Landlord and Owner for the actions of Contractor,
its subcontractors and their respective agents, servants and employees for any
losses suffered by Landlord and Owner which would otherwise have been covered
by any insurance required hereunder in the event Contractor fails to obtain any
such addendum.  (Any subcontractor working directly for Owner shall be deemed a
General Contractor for purposes of this addendum and shall comply with all
obligations herein required of Contractor).


Insurance Addendum
Page 3


Before commencing the Work, Contractor and all subcontractors shall furnish
certificates of insurance satisfactory to Landlord and Owner from each
insurance carrier indicating that the above-required insurance is in force, the
amount of the carrier's liability thereunder, and further providing that the
insurance will not be canceled, changed or non-renewed until the expiration of
at least thirty (30) days after written notice of such cancellation or change
has been mailed to and received by Landlord and Owner.  Contractor shall
deliver copies of all policies from Contractor and Subcontractors if requested
by Landlord and Owner.

All insurance described herein shall be written in a company or companies
satisfactory to Landlord and Owner.  If Contractor or any subcontractor fails
to procure and maintain the above-described insurance, or any portion thereof,
Landlord and Owner shall have the right, but not the obligation to procure and
maintain the required insurance for and in the name of such party and such
party shall pay the cost thereof and shall furnish all information necessary to
acquire and maintain such insurance.  Neither Contractor nor subcontractors
shall violate or knowingly permit any violation of any condition or terms of
the policies of insurance described herein.  All CGL, Auto and Umbrella
Policies shall designate Landlord and Owner as additional insured with
Certificates of Insurance provided as evidence.  Any other insurance maintained
by Landlord and, Owner shall be in excess of all contractors and all tiers of
subcontractor's insurance required herein and shall not contribute with it.

CONTRACTOR(S) shall require all policies of insurance that are in any way
related to the work and that are secured and maintained by Contractor and all
tiers of subcontractors to included clauses providing that each underwriter
shall waive all of its rights of recovery, under subrogation or otherwise
against Landlord and Owner, and shall be so designated on said certificate.

CONTRACTOR SHALL MAINTAIN ALL BUILDER'S RISK INSURANCE COVERAGE FOR DESIGNATED
WORK IN THE AMOUNT OF THE CONTRACT, AND SHALL NAME THE LANDLORD AND OWNER AS
ADDITIONAL NAMED INSURED. ANY DEDUCTIBLE ENCOUNTERED IN THE SUBMISSION OF A
CLAIM SHALL BE BORNE SOLELY BY THE CONTRACTOR.

Landlord and Owner shall not be responsible for obtaining or maintaining in
force insurance on construction equipment, tools or personal effects, owned by
or rented to or in the care, custody and control of Contractor or any
subcontractors, nor shall Landlord and Owner be responsible for such equipment,
tools or personal effects.

All insurance required hereunder shall be maintained continuously until final
completion as certified by Architect and until accepted or approved by Landlord
and Owner.  All insurance shall provide for Owner to take occupancy of the Work
or any part thereof during the term of said insurance.

All policies issued shall specify as additional insured LPC Commercial
Services, Inc., Joshua Realty Corporation and American Management Systems, Inc.


                                  EXHIBIT "D"

                          Concession Fund Voucher Form

         _______________, as Tenant Representative for American Management
Systems, Inc. ("Tenant") hereby certifies to Joshua Realty Corporation
("Landlord") as follows:

         1.      The sum of $__________________ (the "Draw Request") is
requested for disbursement from the Concession Fund and such sum has been
properly expended for items permitted under Article 4.2 of the Lease.  Attached
hereto as Schedule "D-1" is a list of the items for which payment is hereby
requested and the portion of the Draw Request attributable to each such item.

         2.      That the Tenant Work for which the Draw Request is being made
has been performed in accordance with Exhibit "C" to the Lease.

         3.      Attached hereto as Schedule "D-2" are the lien waivers from
all contractors that will be paid by Tenant, or the General Contractor, from
the Draw Request.

         4.      Attached hereto as Schedule "D-3" is the General Contractor's
certification that the Tenant Work for which application for payment is being
made has been completed.


                                  ----------------------------------
                                  Tenant Representative for American
                                  Management Systems, Inc.





                                      D-1


                                  EXHIBIT "E"

                     CLEANING, MAINTENANCE, SPECIFICATIONS,
                             STAFFING AND FREQUENCY


SERVICES

ELEVATORS
(NIGHTLY SERVICES)

1.       Vacuum carpet in all passenger elevators nightly.  Spot clean carpet,
         as necessary.

2.       Carpet to be shampooed as necessary, but no less than once per month.

3.       Elevator carpets to be clean on a nightly basis.

4.       Clean lobby elevator saddles, doors and frames, nightly.  Polish with
         approved Polish, as required.

5.       Clean elevator frames and doors (both sides) of all fingerprints and
         smudges.

6.       Dust and remove all marks on ceiling and light fixtures in cab as
         necessary, but no less than once per week.

7.       Remove all unauthorized marks and writing from insides of elevator
         cabs nightly, using manufacturer's approved method.

8.       Clean all interior cab wall surfaces and wash as required, but no less
         than once per week.

9.       Report all mechanical deficiencies or damage to owners representatives
         on sight.

10.      Remove all gum and foreign matter on sight.

11.      Clean all elevator saddles as required, but no less than once per
         week.

12.      Elevator contractor to clean pits on a monthly basis; the only person
         allowed in the pit is the elevator contractor.

13.      Wet mop and remove all stains from freight elevator flooring.


GENERAL OFFICES
(INCLUDES ALL BASEMENT AREAS)
(NIGHTLY SERVICES)

1.       All flooring swept nightly.





                                      E-1


2.       All carpeted areas and rugs carpet-swept nightly and vacuum-cleaned
         weekly.

3.       Wastepaper baskets, ashtrays, receptacles, etc. emptied and cleaned
         nightly and damp dusted when necessary, but no less than once per
         week.

4.       Cigarette urns, cleaned nightly and sand or water replaced when
         necessary, but no less than once per week.

5.       All furniture, fixture and window sills dusted and wiped cleaned
         nightly.

6.       All glass furniture tops cleaned nightly.

7.       All baseboards, chair rails and trim dusted weekly.

8.       All water fountains washed clean nightly.

9.       Slop sink rooms cleaned nightly.

10.      Fill toilet tissue and towel dispensers as required.

11.      Service sanitary napkin dispensers.  Sanitary napkins and products
         furnished by contractor.  Dispensers shall be maintained by
         contractor.

12.      Collect coins from sanitary napkin dispensers and turn proceeds over
         to duly authorized representative of contractors.

13.      Report all mechanical deficiencies, i.e. dripping faucets, burnt out
         lights, etc. to the Building Manager.


LAVATORIES (PUBLIC)

1.       All flooring swept and washed nightly.

2.       All mirrors, powder shelves, bright work, etc. including flushometers,
         piping and toilet seat hinges washed and polished nightly.

3.       All basins, bowls, urinals and toilet seats (both sides) washed
         nightly.

4.       All partitions, tile walls, dispensers and receptacles dusted nightly.

5.       Paper towels and sanitary disposal receptacles emptied and cleaned
         nightly.

6.       Paper towels, soap dispensers and toilet paper replenished daily or
         more frequently as required.





                                      E-2


HIGH DUSTING - OFFICE AREAS

Do all high dusting approximately once a month, including, but not limited to,
the following:

1.       Dust all pictures, frames, charts, graphs and panel wall hangings not
         reached in nightly cleaning.

2.       Dust all vertical surfaces such as walls, partitions, ventilating
         louvers and other surfaces not reached in nightly cleaning.

3.       Dust all lighting fixtures (exterior only).

4.       Dust all venetian blinds and window frames approximately once every
         two months.


PERIODIC CLEANING - OFFICE AREA

1.       Wipe clean all interior metal as necessary, but no less than once per
         month.

2.       Dust all door louvers and other ventilating louvers within reach
         weekly.

3.       Remove finger marks from metal partition and other surfaces when
         necessary, but no less than once per week.


PERIODIC CLEANING - LAVATORIES (PUBLIC)

1.       Machine-scrub flooring when necessary, but no less than once per
         month.

2.       Wash all partitions, tile walls and enamel surfaces monthly with
         proper disinfectant when necessary, but no less than once per month.

3.       Dust exterior of lighting fixtures monthly.

4.       High dust monthly.


PUBLIC AREAS
(NIGHTLY SERVICES)

1.       All public stairwells to be swept and dusted weekly.

2.       All public stairwells to be washed as necessary, but no less than once
         per month.

3.       Maintain all bright metal.





                                      E-3



BUILDING SERVICE AREAS
(NIGHTLY SERVICES)

1.       Keep locker rooms in neat and orderly condition at all times.  Wash
         lockers once per month.  Wash and wax floor weekly.

2.       Remove all gum and foreign matter from sidewalks on sight.

3.       Lay down and remove runners as necessary.

4.       Remove and clean all spillages.

5.       Wash walls in main floor freight lobby, as required, but no less than
         once per month.  Scrub floor nightly.

6.       Storerooms, electric and telephone closets are to be kept free from
         debris and material.  Floors are to be swept weekly.  Reports of any
         stored extraneous material or equipment are to be made to the Building
         Manager immediately.

7.       Slop sinks, locker areas, etc. to be thoroughly cleaned.

8.       Contractors equipment to be stored in a central location supplied by
         Landlord.

9.       Lights shall be extinguished as areas are cleaned.

10.      Contractor's employees to work behind closed doors at all times.  The
         cleaning supervisor shall inspect all spaces to insure compliance.


LOBBY
(NIGHTLY)

1.       Sweep and remove gum.

2.       Sweep travertine/marble floor nightly (Sunday through Friday).

3.       Remove all hand marks on doors, walls, stairwell doors, directories
         and urns.

4.       Dust all mullions, frames, and ledges with treated cloths.

5.       Wash travertine/marble walls quarterly.

6.       Damp wipe interior black wall surfaces floor to ceiling as required,
         but no less than once per week.

7.       Damp and dry wipe interior of all revolving door drums as required,
         but no less than once per week.





                                      E-4


DAY PORTER SERVICES

Services to be provided by one (1) Day Porter under Building Manager's
direction and supervision.  Duties are as follows:

1.       Police sidewalks.

2.       Police main lobby as required, but no less than three times daily.

3.       Dust and clean out lobby grill work.

4.       Police public areas of multi-tenant floors twice daily.

5.       Damp wipe lobby directories.

6.       Keep entrance door glass clean.

7.       Police men's lavatories on multi-tenant floors as required, but no
         less than twice daily.

8.       Police and vacuum elevator cabs as required, but no less than twice
         daily.

9.       Dust tops of revolving door housing.

10.      Lay down and remove foul weather mats as necessary.

11.      Snow/Ice removal to avoid any accumulation.

12.      Police main lobby on a continual basis.


EXTERMINATION

1.       All services are to be performed by an approved operator licensed by
         Board of Health and certificate of such shall be on file with the
         Building Manager.

2.       Public spaces, slop sink, freight areas, Electric and Telephone
         closets, and mechanical spaces throughout the building shall be kept
         under pest control treatment at least once per month or as required.

3.       All emergency treatments to the above shall be at the expense of the
         contractor.


SECURITY

         The Contractor shall provide security from 5 PM to 8 PM Monday through
         Friday using porter security personnel.  The porter security person
         shall be available at all times to let people in and out.





                                      E-5



         Friday midnight until Saturday midnight - Security Guard S Service.
         Contractor shall provide security services 52 weeks per year including
         all holidays.





                                      E-6


                                  EXHIBIT "F"

                             RULES AND REGULATIONS

         1.      Tenant shall not obstruct or interfere with the rights of
other tenants of the Centerpointe II Building, or of persons having business in
the Centerpointe II Building, or in any way injure or annoy such tenants or
persons.  Tenant will not conduct any activity within the Premises which will
create excessive noise anywhere in the Buildings.

         2.      Canvassing, soliciting and peddling in the Buildings are
prohibited, and Tenant shall cooperate to prevent such activities.

         3.      Tenant shall not bring or keep within the Buildings any
animal, bicycle, motorcycle, or other type of vehicle except as required by
law.

         4.      All office equipment and any other device of any electrical or
mechanical nature shall be placed by Tenant in the Premises in settings
approved by Landlord, so as to absorb or prevent any vibration, noise or
annoyance.  Tenant shall not construct, maintain, use or operate within the
Premises or elsewhere in the Buildings or outside of the Buildings any
equipment or machinery which produces music, sound or noise, which is audible
beyond the Premises.  Tenant shall not cause improper noises, vibrations or
odors within the Buildings.

         5.      Tenant shall not deposit any trash, refuse, cigarettes or
other substances of any kind within or out of the Buildings except in the
refuse containers provided therefor.  No material shall be placed in the trash
boxes or receptacles if such material is of such nature that it may not be
disposed of in the ordinary and customary manner of removing and disposing of
office buildings' trash and garbage without being in violation of any law or
ordinance governing such disposal.  Tenant shall be charged the cost of removal
for any items left by Tenant that cannot be so removed.  All garbage and refuse
disposal shall be made only through entryways and elevators provided for such
purposes and at such times as Landlord shall designate.  Tenant shall not
introduce into the Buildings any substance which might add an undue burden to
the cleaning or maintenance of the Premises or the Buildings.  Tenant shall
exercise its best efforts to keep the sidewalks, entrances, passages, courts,
lobby areas, garages or parking areas, elevators, escalators, stairways,
vestibules, public corridors and halls in and about the Buildings (hereinafter
"Common Areas") clean and free from rubbish.  Tenant shall not cause any
unnecessary labor by reason of Tenant's carelessness or indifference in the
preservation of good order and cleanliness.

         6.      The Common Areas and roof of the Buildings are not for the use
of the general public, and Landlord shall in all cases retain the right to
control or prevent access thereto by all persons whose presence, in the
judgment of Landlord, shall be prejudicial to the safety, character, reputation
or interests of the Buildings and their tenants.  Except as otherwise provided
in the Lease, Tenant shall not enter or install equipment in the mechanical
rooms, air conditioning rooms, electrical closets, janitorial closets or
similar areas or go upon the roof of the Buildings





                                      F-1



without the prior written consent of Landlord.  Except as otherwise provided in
the Lease, Tenant shall not install any radio or television antenna,
loudspeaker or other device on the roof or exterior walls of the Buildings.

         7.      Without limitation upon any of the provisions of the Lease,
Tenant shall not mark, paint, drill into, cut, string wires within, or in any
way deface any part of the Buildings, without the prior written consent of
Landlord, and as Landlord may direct.  Upon removal of any wall decorations or
installations or floor coverings by Tenant, any damage to the walls or floors
shall be repaired by Tenant at Tenant's sole cost and expense.  Tenant shall
not lay linoleum or similar floor coverings so that the same shall come into
direct contact with the floor of the Premises and, if linoleum or similar floor
covering is to be used, an interlining of builder's deadening felt shall be
first affixed to the floor, by a paste or other materials soluble in water.
The use of cement or other similar adhesive material is expressly prohibited.
Floor distribution boxes for electric and telephone wires must remain
accessible at all times.

         8.      Tenant shall not install or permit the installation of any
awnings, shades, mylar films or sunfilters on windows.  Tenant shall cooperate
with Landlord in obtaining maximum effectiveness of the cooling system of the
Buildings by closing drapes and other window coverings when the sun's rays fall
upon windows of the Premises.  Tenant shall not obstruct, alter or in any way
impair the efficient operation of Landlord's heating, ventilating, air
conditioning, electrical, fire, safety or lighting systems, nor shall Tenant
tamper with or change the setting of any thermostat or temperature control
valves in the Buildings.

         9.      Tenant shall not use the washrooms, restrooms and plumbing
fixtures of the Buildings, and appurtenances thereto, for any other purpose
than the purpose for which they were constructed, and Tenant shall not deposit
any sweepings, rubbish, rags or other improper substances therein.  Tenant
shall not waste water by interfering or tampering with the faucets or
otherwise.  If Tenant or Tenant's servants, employees, agents, contractors,
jobbers, licensees, invitees, guests or visitors cause any damage to such
washrooms, restrooms, plumbing fixtures or appurtenances, such damage shall be
repaired at Tenant's expense, and Landlord shall not be responsible therefor.

         10.     Subject to applicable fire or other safety regulations, all
doors opening onto Common Areas and all doors upon the perimeter of the
Premises shall be kept closed and, during non-business hours, locked, except
when in use for ingress or egress.

         11.     Employees of Landlord shall not receive or carry messages for
or to Tenant or any other person, nor contract with nor render free or paid
services to Tenant or Tenant's servants, employees, contractors, jobbers,
agents, invitees, licensees, guests or visitors.  In the event that any of
Landlord's employees perform any such services, such employees shall be deemed
to be the agents of Tenant regardless of whether or how payment is arranged for
such services.

         12.     Tenant shall, upon the termination of its tenancy, provide
Landlord with the combinations to all combination locks on safes, safe cabinets
and vaults and deliver to Landlord all keys to the Buildings, the Premises and
all interior doors, cabinets and other key-controlled mechanisms therein,
whether or not such keys were furnished to Tenant by Landlord.  In the





                                      F-2


event of the loss of any key furnished to Tenant by Landlord, Tenant shall pay
to Landlord the cost of replacing the same or of changing the lock or locks
opened by such lost key if Landlord shall deem it necessary to make such a
change.  The word "key" as used herein shall refer to keys, keycards and all
such means of obtaining access through restricted access systems.

         13.     For purposes hereof, the terms "Landlord", "Tenant",
"Buildings" and "Premises" are defined as those terms are defined in the Lease
to which these Rules and Regulations are attached.  The term "Buildings" shall
include the Premises, and any obligations of Tenant hereunder with regard to
the Buildings shall apply with equal force to the Premises and to other parts
of the Buildings.

         14.     These Rules and Regulations are in addition to, and shall not
be construed to in any way modify or amend, in whole or in part, the
agreements, covenants, conditions and provisions of any lease of premises in
the Buildings.  The terms of the Lease shall supersede any provisions of these
Rules and Regulations which may be inconsistent with the terms of the Lease.





                                      F-3



                                  EXHIBIT "G"

                          HVAC System Design Criteria




SUMMER                                                WINTER

                                                                                
    Outside Temperature                                    Outside Temperature

            Dry Bulb               95 degrees F                    Dry Bulb               O degrees F
            Wet Bulb               78 degrees F

    Inside Temperature                                     Inside Temperature

            Dry Bulb               75 degrees F                    Dry Bulb               70 degrees F
            % Relative Humidity    50%                             % Relative Humidity    20%






                                      G-1


                                   EXHIBIT H

                       Legal Description of the Property

PARCEL A: BEGINNING at a point on the Southwesterly R/W line of Legato Road
(Route #656) said point being N 14 deg. 30' 12" W 72.49 feet from a point
marking the Northeasterly corner of the Fairfax Assembly of Good Church; thence
departing from the Road and running through the property of Faircenter Limited
Partnership the following courses: with a curve to the right whose radius is
26.00 feet (and whose chord is S 65 deg. 28' 14" W, 11.22 feet) an arc distance
of 11.31 feet; S 77 deg, 55' 48" W 200.47 feet; with a curve to the right whose
radius is 659.96 feet (and whose chord is S 86 deg. 10' 48" W, 189.40 feet) an
arc distance of 190.05 feet and N 08 deg. 21' 54" E 564.80 feet to a point on
the aforementioned Southwesterly R/W line of Legato Road; thence with the
Southwesterly line of Legato Road S 59 deg. 03' 43" E 129 feet and with a curve
to the right whose radius is 344.62 feet (and whose chord is S 56 deg. 04' 19"
E 35.95 feet) an arc distance of 35.97 feet to a point; thence departing from
the Road and running through the property of Faircenter Limited Partnership
with a curve to the left whose radius is 55.00 feet (and whose chord is S 48
deg. 51' 01" E 50.86 feet) an arc distance of 52.87 feet to a point on the
Southwesterly R/W line of Legato Road; thence with the Southwesterly R/W line
of Legato Road the following courses: with a curve to the right whose radius is
344.62 feet (and whose chord is S 40 deg. 30' 20" E 49.45 feet) an arc distance
of 49.49 feet; S 24 deg. 09' 12" E 84.71 feet; S 16 deg. 09' 12" E 147.80 feet;
S 11 deg. 30' 12" E 100.00 feet and S 14 deg. 30' 12" E 25.71 feet to the point
of beginning, containing 144,883 square feet of land, more or less.





                                      H-1


                                   EXHIBIT H

BEGINNING at a point marking the intersection of the Southeasterly R/W line of
West Ox Road (Route #608) and the Southwesterly R/W line of Legato Road (Route
#656) ; thence with the Southwesterly R/W line of Legato Road S 59# 03' 43" E,
39.90 feet to a point; thence departing from the Road and running through the
property of Faircenter Limited Partnership S 08# 21' 54" W, 564.80 feet to a
point on the Northerly line of relocated Legato Road; thence with the said line
of relocated Legato Road the following courses: with a curve to the right whose
radius is 659.96 feet (and whose chord is N 78# 05' 37" W, 171.74 feet) and arc
distance of 172.22 feet; with a curve to the right whose radius is 420.00 feet
(and whose chord is N 62# 58' 47" W, 111.65 feet) an arc distance of 111.98
feet; with a curve to the right whose radius is 4500.00 feet (and whose chord
is N 55# 04' 04" W, 43.00 feet) an arc distance of 43.00 feet; N 47# 02' 47" W,
92.84 feet and with a curve to the right whose radius is 41.00 feet (and whose
chord is N 03# 10' 33" E, 63.02 feet) an arc distance of 71.88 feet to a point
on the aforementioned R/W line of West Ox Road; thence with the said R/W line
of West Ox Road N 53# 23' 54" E, 361.12 feet and with a curve to the left whose
radius is 582.96 feet (and whose chord is N 44# 35' 50" E, 178.39 feet) an arc
distance of 179.09 feet to the point of beginning, containing 140,326 square
feet of land.

                 TOGETHER WITH all rights appurtenant to the property described
above arising under a Declaration of Easements, Covenants and Related
Agreements, made by Faircenter Limited Partnership, a Delaware limited
partnership, dated as of February 2, 1989, and recorded February 15, 1989 in
the Clerk's Office of the Circuit Court of Fairfax County, Virginia in Deed
Book 7265, at page 1813.





                                      H-2


                                  EXHIBIT "I"

                             INDEX OF DEFINED TERMS



        TERM                                     ARTICLES IN WHICH DEFINED
- - -------------------------                        -------------------------

                                                  
Acceptance Notice                                    61

Accepted First Offer Space                           61.3

ADA                                                  4.1

Additional Rent                                      7.1.4

Affiliate                                            50.1

Annual Base Rent                                     54.1

Annual Operating Costs                               7.4.1

Availability Date                                    61.4

Base Building Modifications                          Exhibit "B"

Base Rent                                            1.2,6

Base Year Assessment                                 7.1.1(e)

Base Year Real Estate Taxes                          1.3.2

Base Year Operating Expenses                         1.3.1,54.2

Buildings                                            1.1(c), 50.2

Centerpointe I Building                              1.1(a)

Centerpointe II Building                             1.1(b)

Centerpointe I Net Annual Operating Costs            7.4(a)

Centerpointe II Net Annual Operating Costs           7.4(b)

Centerpointe I Net Real Estate Taxes                 7.1.1(a)

Centerpointe II Net Real Estate Taxes                7.1.1(b)

Centerpointe I Premises                              1.1(a)






                                      I-1





        TERM                                     ARTICLES IN WHICH DEFINED
- - -------------------------                        -------------------------

                                                  
Centerpointe II Premises                             1.1(b)

Concession Fund                                      1.5, 4.2

Concession Fund Voucher Form                         4.2, Exhibit I'D"

Control Areas                                        52.1

County                                               4.3

Core Elements                                        4.1

Environmental Statutes                               52.1

Escalation Date                                      6.3

Escalation Period                                    6.3

Expansion Notice                                     62.1

Expansion Space                                      62.1

Expansion Space Lease Commencement Date              62.3

Expansion Space Rent Commencement Date               62.4

Extension Exercise Notice                            54.1

First Lease Year                                     3.3

First Offer Space                                    61

Five Year Space                                      62.5

Hard Costs                                           4.2

Hazardous Substances                                 52.4

Holdover Payment                                     4.3

Holidays                                             50.3

HVAC Off-Hours                                       9.1.1

HVAC Off-Hours Rate                                  50.4

Initial Space                                        1.4






                                      I-2




        TERM                                     ARTICLES IN WHICH DEFINED
- - -------------------------                        -------------------------

                                                  
Landlord                                             Introductory Paragraph
                                                     (page 1); 50.5

Landlord's Address                                   1.9(b)

Landlord's Control Area                              52.1

Last Lease Year                                      3.3

Late Charge                                          8

Lease Commencement Date                              3.1

Lease Interest Rate                                  50.6

Lease Taxes                                          7.1.2,50.7

Lease Year                                           3.3

Market Rental Value                                  54.3,54.3.2

Monthly Installment of Base Rent                     6.1.1

Mortgage                                             35.1

Negotiation Period                                   54.3

Net Annual Operating Costs                           7.4(c)

Net Real Estate Taxes                                7.1.1(c)

Occupancy Schedule                                   1.4

Offer Notice                                         61

Operating Expenses                                   54.2

Option Exercise Date                                 54.1

Ordinary Business Hours                              50.8

Overlessor                                           36

Permitted Use                                        1.8

Premises                                             1.1(c)






                                      I-3





        TERM                                     ARTICLES IN WHICH DEFINED
- - -------------------------                        -------------------------

                                                  
Prime Rate                                           50.9

Property                                             50.10

Proposed Recapture Space                             14.5

Proposed Transfer Date                               14.5

Real Estate Taxes                                    7.1.1,50.11

Recapture Notice                                     14.5

Renewal Period                                       54.1

Rent                                                 50.12

Rent Commencement Date                               3.2.1

Rentable Area of the Buildings                       50.13

Rentable Area of the Premises                        1.1(c), 50.14

Responsible Party                                    52.1

Right of First Offer                                 61

Scheduled Commencement Date                          61

Scheduled Rent Commencement Date                     1.4

Security Deposit                                     1.6

Senior Holder                                        58

Subsequent Escalation Date                           6.3

Subsequent Lease Commencement Date                   3.2,61.4

Subsequent  Rent Commencement Date                   3.2.2

Subsequent  Space                                    1.4

Substitute  Space                                    22.1

Substitute  Space Differential                       22.1

Substitute  Space Tenant                             22.1






                                      I-4




        TERM                                     ARTICLES IN WHICH DEFINED
- - -------------------------                        -------------------------

                                                  
Taking Date                                          24.1

Tax Appeal                                           7.1.1(d)

Tenant                                               Introductory Paragraph
                                                     (page 1); 50.15

Tenant Design and Construction Process               Exhibit 'IC"

Tenant Electricity                                   7.1.3

Tenant Electricity Costs                             7.1.3

Tenant Work                                          4.2

Tenant's Address                                     1.9(a)

Tenant's Centerpointe I Proportionate Share          7.1.1(a), 50.16.1

Tenant's Centerpointe II Proportionate Share         7.1.1(b), 50.16.2

Tenant's Control Area                                52.1

Tenant's Proportionate Share                         50.16

Term                                                 3.1

Termination Date                                     3.1

Three Year Average Assessment                        7.1.1(e)

Wilson Boulevard Lease                               4.3






                                      I-5



                                   EXHIBIT J

                              MEMORANDUM OF LEASE

         THIS MEMORANDUM OF LEASE is made as of this ________ day of August,
1992, by and between JOSHUA REALTY CORPORATION, a Delaware corporation
("Landlord"), and AMERICAN MANAGEMENT SYSTEMS, INC., a Delaware corporation
('Tenant"), with respect to the following recitals:

         A.      Landlord is the owner of the land and improvements located in
Fairfax County, Virginia at 4050 and 4000 Legato Road, as more fully described
in Exhibit A attached hereto.

         B.      Pursuant to a lease of even date herewith (the "Lease'),
Landlord has leased to Tenant all of the rentable area of the building situated
at 4050 Legato Road and approximately 38,384 square feet of rentable area in
the building situated at 4000 Legato Road.  The Lease grants Tenant certain
expansion rights in the building situated at 4000 Legato Road.

         C.      Landlord and Tenant desire to provide record notice of the
Lease.

         NOW THEREFORE, in consideration of the premises and other good and
adequate consideration, receipt of which is acknowledged, Landlord and Tenant
agree and acknowledge as follows:

         1.      Landlord and Tenant have entered into the Lease.

         2.      The initial term of the Lease is for fifteen (15) years
                 commencing on the date hereof.  The Lease grants Tenant the
                 option to extend the term of the Lease for two (2) five-year
                 renewal periods.

         3.      This Memorandum of Lease describes certain provisions
                 contained in the Lease.  Reference is hereby made to the Lease
                 for the complete statement of all terms and conditions
                 contained therein.

         4.      In no event shall this Memorandum of Lease be used to
                 interpret or construe the terms of the Lease, the sole purpose
                 of this Memorandum of Lease being to provide recordable notice
                 of the Lease.





                                      J-1



         IN WITNESS WHEREOF, Landlord and Tenant have caused this Memorandum of
Lease to be executed and delivered as of the date and year first above written.


ATTEST:                                     Landlord:

                                            JOSHUA REALTY CORPORATION,
                                            a Delaware corporation

                                            By:
- --------------------------------                --------------------------------
      (Corporate Seal)                         Steven D. Burton, Vice President


                                            Tenant:

                                            AMERICAN MANAGEMENT SYSTEMS, INC.,
                                            a Delaware corporation

                                            By:
- --------------------------------                --------------------------------
      (Corporate Seal)
                                            Title:
                                                  -----------------------------

Title:





                                      J-2


                     FIRST AMENDMENT TO AGREEMENT OF LEASE
                     BETWEEN JOSHUA REALTY CORPORATION AND
                       AMERICAN MANAGEMENT SYSTEMS, INC.

         This First Amendment to Agreement of Lease is made this 24th day of
May, 1993, between JOSHUA REALTY CORPORATION, a Delaware corporation (general
partner and sole remaining partner of Faircenter Limited Partnership, a
Delaware limited partnership) (hereinafter referred to as "Landlord"), and
AMERICAN MANAGEMENT SYSTEMS, INC., a Delaware corporation (hereinafter referred
to as "Tenant").

                              B A C K G R O U N D:

         A.      Landlord and Tenant entered into a certain Agreement of Lease
dated August 10, 1992 (the "Lease").  Capitalized terms used in this First
Amendment and not defined shall have the meanings ascribed to them under the
Lease.

         B.      Tenant has exercised Tenant's option to lease the Expansion
Space pursuant to Paragraph 62 of the Lease.

         C.      Landlord and Tenant desire that Tenant lease from Landlord
approximately 2,893 square feet on the eighth floor of the Centerpointe II
Building and Landlord and Tenant agree to amend the Lease by adding Paragraph
66 to the Lease as hereinafter provided:

         66.     Eighth Floor Space.

                          66.1    Landlord hereby leases, to Tenant, and Tenant
                 hereby hires and takes from Landlord, approximately 2,893
                 square feet on the eighth floor of the Centerpointe II
                 Building which shall herein be defined as the "Eighth Floor
                 Space".  Landlord shall make available the Eighth Floor Space
                 to Tenant for Tenant Work upon the full execution of this
                 First Amendment.  All of the terms and condition of the Lease
                 applicable to the Premises shall apply to such Eighth Floor
                 Space, except as set forth below in this Article.  The Eighth
                 Floor Space shall be delivered to Tenant in its then "as-is"
                 condition and state of repair.

                          66.2    For purposes of the Eighth Floor Space, the
                 Concession Fund shall equal Eighteen Dollars ($18.00) per
                 rentable square foot.  All other provisions in the Lease
                 governing the Concession Fund shall apply to the Eighth Floor
                 Space.

                          66.3    The Term of the Lease shall commence as to
                 the Eighth Floor Space on May 1, 1993 ("Eighth Floor Space
                 Lease Commencement Date").

                          66.4    Tenant's obligation to pay Rent for the
                 Eighth Floor Space shall commence on March 1, 1994 ("Eighth
                 Floor Space Rent Commencement Date").  During the period
                 between the Eighth Floor Space Lease Commencement Date and the
                 Eighth Floor Space Rent Commencement Date, Tenant shall pay to
                 Landlord an amount equal to Five Dollars ($5.00) per rentable
                 square foot per annum, in equal monthly installments, in
                 advance, as Additional Rent hereunder.

                 All other obligations of Tenant pertaining to the Eighth Floor
                 Space under the Lease shall commence on the Eighth Floor Space
                 Lease Commencement Date.

                          66.5    After the Eighth Floor Space Rent
                 Commencement Date, Tenant's Centerpointe II Proportionate
                 Share shall be increased by an amount equal to the percentage
                 derived by dividing the rentable square footage of the Eighth
                 Floor Space by 203,630.

                          66.6    Except as modified by this First Amendment,
                 the Lease shall otherwise remain in full force and effect.

         IN WITNESS WHEREOF, and intending to be legally bound hereby, the
parties hereto have executed this First Amendment to Lease on the date first
set forth herein.

                                  LANDLORD:

                                  JOSHUA REALTY CORPORATION,
                                  a Delaware corporation

                                  By:      /s/ Steven D. Burton
                                           --------------------------------
                                           Steven D. Burton, Vice President


                                  TENANT:

                                  AMERICAN MANAGEMENT SYSTEMS, INC.,
                                  a Delaware corporation

                                  By:      /s/ Frank A. Nicolai
                                           --------------------------------

                                  Title:
                                           --------------------------------

- - -----------------------

- - -----------------------

         I, the undersigned Notary Public in and for the above-named
jurisdiction, hereby certify that Steven D. Burton, who executed the foregoing
memorandum of Lease dated August __, 1992 in his capacity as Vice President of
Joshua Realty Corporation, personally appeared before me in my aforesaid
jurisdiction and acknowledged the same as his free act and deed and the act and
deed of said corporation.


                                  ----------------------------------
                                  Notary Public               [SEAL]

                                  My commission expires:

                                  ----------------------------------


- - -----------------------

- - -----------------------

         I, the undersigned Notary Public in and for the above-named
jurisdiction, hereby certify that _________________, who executed the foregoing
Memorandum of Lease dated August __, 1992 in his capacity as [Vice] President
of American Management Systems, Inc., personally appeared before me in my
aforesaid jurisdiction and acknowledged the same as his free act and deed and
the act and deed of said corporation.


                                  ----------------------------------
                                  Notary Public               [SEAL]

                                  My commission expires:

                                  ----------------------------------

                     SECOND AMENDMENT TO AGREEMENT OF LEASE
                     BETWEEN JOSHUA REALTY CORPORATION AND
                       AMERICAN MANAGEMENT SYSTEMS, INC.

                 This Second Amendment to Agreement of Lease is made this 18th
day of March, 1994, between JOSHUA REALTY CORPORATION, a Delaware corporation
(general partner and sole remaining partner of Faircenter Limited Partnership,
a Delaware limited partnership) (hereinafter referred to as "Landlord"), and
AMERICAN MANAGEMENT SYSTEMS, INC., a Delaware corporation (hereinafter referred
to as "Tenant").

                              B A C K G R 0 U N D:

                 A.       Landlord and Tenant entered into a certain Agreement
of Lease dated August 10, 1992, as amended by a First Amendment to Agreement of
Lease dated May 24, 1993 (together the "Lease").  Capitalized terms used in
this Second Amendment and not defined shall have the meanings ascribed to them
under the Lease.

                 B.       Landlord and Tenant desire to amend and restate
Article 6.3 of the Lease to modify the basis upon which the escalation of Base
Rent may occur during the Term of the Lease.

                 NOW THEREFORE, for good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, Landlord and Tenant
amend the Lease by amending and restating Article 6.3 as hereinafter provided:

                          "6.3    Escalation of Base Rent.

                                  6.3.1  Commencing on May 1, 1994 ("Escalation
                          Date"), and on the first day of May during the Term
                          thereafter (each a "Subsequent Escalation Date")
                          (each such period from and after the Escalation Date
                          to the date which is one day prior to the next
                          Subsequent Escalation Date being herein defined as an
                          "Escalation Period"), subject to Article 6.3.2 below,
                          Base Rent per rentable square foot shall be increased
                          for each Escalation Period by an amount equal to
                          Three and Eight Hundred Twenty-five one thousandths
                          percent (3.825%) (the "Escalation Percentage")
                          multiplied by the difference between (i) Base Rent
                          per rentable square foot, at the rate effective on
                          the day before the applicable Subsequent Escalation
                          Date and (ii) the sum of the Base Year Operating
                          Expenses and Base Year Real Estate Taxes

                          per rentable square foot.  By way of illustration of
                          the foregoing formula, if the sum of the Base Year
                          Operating Expenses and Base Year Real Estate Taxes
                          per rentable square foot is Four Dollars and
                          Forty-five cents ($4.45), then on the Escalation Date
                          Base Rent per rentable square foot will increase to
                          $14.05 per rentable square foot from and after the
                          Escalation Date until the next Subsequent Escalation
                          Date.

                                  6.3.2   The selection of an Escalation
                          Percentage of Three and Eight Hundred Twenty-five one
                          thousandths percent (3.825%) assumes that the sum of
                          the Base Year Operating Expenses and the Base Year
                          Real Estate Taxes will equal Four Dollars and
                          Forty-five cents ($4.45). The Escalation Percentage
                          will be adjusted if the actual sum of Base Year
                          Operating Expenses and Base Year Real Estate Taxes is
                          not four Dollars and Forty-five Cents ($4.45) to that
                          percentage which will produce a series of Base Rent
                          cash flows, the net present value of which shall
                          equal the net present value of Base Rent over the
                          primary term of the Lease, as defined in the Lease
                          prior to this Second Amendment, using a discount rate
                          in both net present value calculations equal to eight
                          percent (8%).  The Escalation Percentage will also be
                          readjusted if, pursuant to Article 7.1.1(e) of the
                          Lease, the Base Year Real Estate Taxes are
                          subsequently adjusted.  Schedule A attached to this
                          Second Amendment illustrates the manner in which the
                          Escalation Percentage may be adjusted in the event
                          that the actual sum of Base Year operating Expenses
                          and Base Year Real Estate Taxes is not Four Dollars
                          and Forty-five Cents ($4.45)."

                 IN WITNESS WHEREOF, and intending to be legally bound hereby,
the parties hereto have executed this Second Amendment to Lease on the date
first set forth herein.  Except as amended hereby, the Lease remains in full
force and effect.

                                  LANDLORD:

                                  JOSHUA REALTY CORPORATION,
                                  a Delaware corporation

                                  By:  /s/ Steven D. Burton
                                       ----------------------
                                       Steven D. Burton, Vice
                                       President

                      [SIGNATURES CONTINUED ON NEXT PAGE]

                   [SIGNATURES CONTINUED FROM PREVIOUS PAGE]

                                  TENANT:

                                  AMERICAN MANAGEMENT SYSTEMS, INC.,
                                  a Delaware corporation

                                  By: /s/ Frank A. Nicolai
                                      ------------------------------

                                  Title:  Executive Vice President
                                          --------------------------

Schedule A



INITIAL ESCALATION                                                                  260,000 square feet
         Base Year Taxes & Expenses         $4.45
         Per Square Foot                    $9.25
         Rate of escalation                3.825%

         Interest Rate                        8.0                               YEARS
                        NPV            1            2            3            4            5            6
                ----------------------------------------------------------------------------------------------------------
                                                                           
Current Lease    25,715,912    2,405,000    2,459,113    2,514,443    2,571,017    2,618,885    2,948,015
Proposed Terms   25,715,912    2,405,000    2,496,982    2,592,483    2,691,635    2,794,580    2,901,463
- - --------------------------------------------------------------------------------------------------------------------------




INITIAL ESCALATION
         Base Year Taxes & Expenses         $4.45
         Per Square Foot                    $9.25
         Rate of escalation                3.825%

         Interest Rate                        8.0                               YEARS
                         7            8            9           10           11           12
                ----------------------------------------------------------------------------------------------------------
                                                                
Current Lease    3,014,345    3,082,168    3,151,517    3,222,426     3,814,30    3,900,766
Proposed Terms   3,012,433    3,127,647    3,247,268    3,371,464    3,500,410    3,634,287
- - ---------------------------------------------------------------------------------------------------------------------------




INITIAL ESCALATION
         Base Year Taxes & Expenses         $4.45
         Per Square Foot                    $9.25
         Rate of escalation                3.825%

         Interest Rate                        8.0                  YEARS
                        13          14           15
                ----------------------------------------------------------------------------------------------------------
                                
Current Lease    3,988,534   4,078,276    4,170,037
Proposed Terms   3,773,285   3,917,600    4,067,433
- - --------------------------------------------------------------------------------------------------------------------------




- - --------------------------------------------------------------------------------------------------------------------------
Example #1
         Base Year Taxes & Expenses         $4.60
         Per Square Foot                    $9.10
         Rate of escalation                3.849%

         Interest Rate                        8.0                               YEARS
                        NPV            1            2            3            4            5            6
                ----------------------------------------------------------------------------------------------------------
                                                                          
Current Lease    25,336,182    2,366,000    2,419,235    2,473,668    2,529,325    2,586,235    2,904,425
Proposed Terms   25,336,182    2,366,000     2,457,08    2,551,641    2,649,854    2,751,847    2,857,766
- - --------------------------------------------------------------------------------------------------------------------------




- - --------------------------------------------------------------------------------------------------------------------------
Example #1
         Base Year Taxes & Expenses         $4.60
         Per Square Foot                    $9.10
         Rate of escalation                3.849%

         Interest Rate                        8.0                               YEARS
                         7            8            9           10           11           12
                ----------------------------------------------------------------------------------------------------------
                                                               
Current Lease    2,969,775    3,036,595    3,104,918    3,174,779    3,766,212    3,850,951
Proposed Terms   2,967,762    3,081,991    3,200,618    3,323,810    3,451,744    3,584,602
- - --------------------------------------------------------------------------------------------------------------------------




- - --------------------------------------------------------------------------------------------------------------------------
Example #1
         Base Year Taxes & Expenses         $4.60
         Per Square Foot                    $9.10
         Rate of escalation                3.849%

         Interest Rate                        8.0                YEARS
                        13          14           15
                ----------------------------------------------------------------------------------------------------------
                                 
Current Lease    3,937,598   4,026,194    4,116,783
Proposed Terms   3,722,574   3,885,856    4,014,653
- - --------------------------------------------------------------------------------------------------------------------------




- - --------------------------------------------------------------------------------------------------------------------------
Example #2
         Base Year Taxes & Expenses         $4.75
         Per Square Foot                    $8.95
         Rate of escalation                3.880%

         Interest Rate                        8.0                               YEARS
                        NPV            1            2            3            4            5            6
                ----------------------------------------------------------------------------------------------------------
                                                                          
Current Lease    24,956,453    2,327,000    2,379,358    2,432,893    2,487,633    2,543,605    2,860,836
Proposed Terms   24,965,453    2,327,000    2,417,291    2,511,085    2,608,519    2,709,733    2,814,874
- - --------------------------------------------------------------------------------------------------------------------------




- - --------------------------------------------------------------------------------------------------------------------------
Example #2
         Base Year Taxes & Expenses         $4.75
         Per Square Foot                    $8.95
         Rate of escalation                3.880%

         Interest Rate                        8.0                               YEARS
                         7            8            9           10           11           12
                ----------------------------------------------------------------------------------------------------------
                                                                
Current Lease    2,925,205    2,991,022    3,058,320    3,127,132    3,717,493    3,801,136
Proposed Terms   2,924,095    3,037,554    3,155,415    3,277,849    3,405,035    3,537,155
- - --------------------------------------------------------------------------------------------------------------------------




- - --------------------------------------------------------------------------------------------------------------------------
Example #2
         Base Year Taxes & Expenses         $4.75
         Per Square Foot                    $8.95
         Rate of escalation                3.880%

         Interest Rate                        8.0                YEARS
                        13          14           15
                ----------------------------------------------------------------------------------------------------------
                                
Current Lease    3,886,662   3,974,112    4,063,529
Proposed Terms   3,674,401   3,816,973    3,965,077
- - --------------------------------------------------------------------------------------------------------------------------




- - --------------------------------------------------------------------------------------------------------------------------
Example #3
         Base Year Taxes & Expenses         $4.30
         Per Square Foot                    $9.40
         Rate of escalation                3.801%

         Interest Rate                        8.0                               YEARS
                        NPV            1            2            3            4            5            6
                ----------------------------------------------------------------------------------------------------------
                                                                           
Current Lease    26,095,641    2,444,000    2,498,990    2,555,217    2,612,710    2,671,496    2,991,604
Proposed Terms   26,095,641    2,444,000    2,536,896    2,633,323    2,733,414    2,837,311    2,945,156
- - --------------------------------------------------------------------------------------------------------------------------




- - --------------------------------------------------------------------------------------------------------------------------
Example #3
         Base Year Taxes & Expenses         $4.30
         Per Square Foot                    $9.40
         Rate of escalation                3.801%

         Interest Rate                        8.0                               YEARS
                         7            8            9           10           11           12
                ----------------------------------------------------------------------------------------------------------
                                                                
Current Lease    3,058,915    3,127,741    3,198,115    3,270,073    3,863,649    3,950,581
Proposed Terms   3,057,101    3,173,300    3,293,917    3,419,117    3,549,077    3,683,977
- - --------------------------------------------------------------------------------------------------------------------------




- - --------------------------------------------------------------------------------------------------------------------------
Example #3
         Base Year Taxes & Expenses         $4.30
         Per Square Foot                    $9.40
         Rate of escalation                3.801%

         Interest Rate                        8.0                 YEARS
                        NPV           13          14           15
                ----------------------------------------------------------------------------------------------------------
                                           
Current Lease    26,095,641    4,039,470   4,130,358    4,223,291
Proposed Terms   26,095,641    3,824,004   3,969,353    4,120,227
- - --------------------------------------------------------------------------------------------------------------------------


                     THIRD AMENDMENT TO AGREEMENT OF LEASE
                     BETWEEN JOSHUA REALTY CORPORATION AND
                       AMERICAN MANAGEMENT SYSTEMS, INC.

         This Third Amendment to Agreement of Lease is made this 5th day of
June, 1995, between JOSHUA REALTY CORPORATION, a Delaware corporation (general
partner and sole remaining partner of Faircenter Limited Partnership, a
Delaware limited partnership) (hereinafter referred to as "Landlord"), and
AMERICAN MANAGEMENT SYSTEMS, INC., a Delaware corporation (hereinafter referred
to as "Tenant").

                                   BACKGROUND

         A.      Landlord and Tenant entered into a certain Agreement of Lease
dated August 10, 1992, as amended by a First Amendment to Agreement of Lease
dated May 24, 1993 and by a Second Amendment to Agreement of Lease dated March
18, 1994 (as amended, the "Lease").  Capitalized terms used in this Third
Amendment and not deemed shall have the meanings ascribed to them under the
Lease.

         B.      Landlord and Tenant desire that Tenant lease from Landlord
approximately 4,393 rentable square feet on the fifth floor of the Centerpointe
II Building and Landlord and Tenant agree to amend the Lease by adding
Paragraph 67 to the Lease as hereinafter provided:

                 67.      Fifth Floor Space.

                          67.1    Landlord hereby leases to Tenant, and Tenant
                 hereby hires and takes from Landlord, approximately 4,393
                 rentable square feet on the fifth floor of the Centerpointe II
                 Building more fully described on the floor plan annexed to
                 this Third Amendment as Exhibit A, which shall herein be
                 deemed as the "Fifth Floor Space." Landlord shall make
                 available the Fifth Floor Space to Tenant for Tenant Work on
                 June 1, 1995.  All of the terms and conditions of the Lessee
                 applicable to the Premises shall apply to such Fifth Floor
                 Space, except as set forth below in this Article.

                          67.2.1   The Fifth Floor Space will be delivered to
                 Tenant in its "as is", "as built" condition and state of
                 repair.  Any mixtures not removed by the prior tenant shall be
                 left in place and not removed by Landlord.  Tenant shall
                 perform the Fifth Floor Tenant's Work (which term shall mean
                 the provision of materials, components, labor and services
                 encompassed within the work described on Exhibit B to this
                 Third Amendment) (i) at Tenant's sole cost, except as provided
                 in Paragraph

                 67,2.2, and (ii) in accordance with the Tenant Design and
                 Construction Process set forth on Exhibit "C" to the Lease and
                 otherwise in accordance with all relevant provisions of the
                 Lease.  To the extent required by law, Landlord will comply
                 with the requirements of the ADA applicable to the Core
                 Elements of Centerpointe H which may arise because of the
                 performance of the Fifth Floor Tenant's Work and Tenant shall
                 comply with all other ADA requirements respecting the Fifth
                 Floor Space, including those requirements arising from the
                 Fifth Floor Tenant's Work.

                          67.2.2  For purposes of the Fifth Floor Space, the
                          Concession Fund shall equal Seven Dollars ($7.00) per
                          rentable square foot.  All other provisions in the
                          Lease governing the Concession Fund shall apply to
                          the Fifth Floor Space.

                          67.3    The Term of the Lease shall commence as to
                          the Fifth Floor Space on June 1, 1995 ("Fifth Floor
                          Space Lease Commencement Date").  The Term of the
                          Lease as to the Fifth Floor Space shall expire on the
                          date which is four (4) years and seven (7) months
                          after the Fifth Floor Space Rent Commencement Date.

                          67.4    Base Rent payable for the Fifth Floor Space
                          shall be fifteen dollars and sixty cents ($15.60) per
                          rentable square foot, net of Electricity Costs, and
                          subject to adjustment as described in article 6.4.
                          Base Rent for the Fifth Floor Space shall be payable
                          as provided in Section 6.1.1. Tenant's obligation to
                          pay Rent for the Fifth Floor Space shall commence_on
                          the earlier of (i) July 15, 1994 or (ii) substantial
                          completion of the Fifth Floor Tenant's Work ("Fifth
                          Floor Space Rent Commencement Date").  All other
                          obligations of Tenant pertaining to the Fifth Floor
                          Space under the Lease shall commence on the Fifth
                          Floor Space Rent Commencement Date.  If the Fifth
                          Floor Space Rent Commencement Date is other than the
                          First day of a month, Base Rent for the Fifth Floor
                          Space due from the Fifth Floor Space Rent
                          Commencement Date until the first day of the
                          following month shall be prorated and payable on the
                          Fifth Floor Space Rent Commencement Date.

                          67.5    After the Fifth Floor Space Rent Commencement
                          Date, Tenant's Centerpointe II Proportionate Share
                          shall be increase by an amount equal to the

                          percentage derived by dividing the rentable square
                          footage of the Fifth Floor Space by 204,481.
                          Therefore, after the Fifth Floor Space Rent ,
                          Tenant's Centerpointe H Proportionate Share shall
                          equal 31.40%.

                          67.6    Except as modified by this Third Amendment,
                          the Lease shall otherwise remain in full force and
                          effect.

         IN WITNESS WHEREOF, and intending to be legally bound hereby, the
parties hereto have executed this Third Amendment to Lease on the date on the
date first set forth herein.


                                  LANDLORD:

                                  JOSHUA REALTY CORPORATION,
                                  a Delaware Corporation

                                  By:  /s/    Gerald Karr
                                       -----------------------
                                       Name:  Gerald Karr
                                       Title: Vice President


                                  TENANT:

                                  AMERICAN MANAGEMENT SYSTEMS, INC.,
                                  a Delaware Corporation

                                  By:  /s/    Frank A. Nicolai
                                       -----------------------
                                       Name:  Frank A. Nicolai
                                       Title: EVP

[THE FOLLOWING PAGES INCLUDED AS EXHIBITS A AND B FLOOR PLANS OF THE PREMISES.]

                     FOURTH AMENDMENT TO AGREEMENT OF LEASE
                     BETWEEN JOSHUA REALTY CORPORATION AND
                       AMERICAN MANAGEMENT SYSTEMS, INC.

                 This Fourth Amendment to Agreement of Lease is made this 18th
day of July, 1995, between JOSHUA REALTY CORPORATION, a Delaware corporation
(general partner and sole remaining partner of Faircenter Limited Partnership,
a Delaware limited partnership) (hereinafter referred to as "Landlord"), and
AMERICAN MANAGEMENT SYSTEMS, INC., a Delaware corporation (hereinafter referred
to as "Tenant").

                                   BACKGROUND

                 A.       Landlord and Tenant entered into a certain Agreement
of Lease dated August 10, 1992, as amended by a First Amendment to Agreement of
Lease dated May 24, 1993, by a Second Amendment to Agreement of Lease dated
March 18, 1994 and by a Third Amendment to Agreement of Lease Dated June 5,
1995 (as amended, the "Lease").  Capitalized terms used in this Fourth
Amendment and not defined shall have the meanings ascribed to them under the
Lease.

                 B.       Landlord and Tenant desire that Tenant lease from
Landlord approximately 1,697 rentable square feet on the ninth floor of the
Centerpointe II Building known as suite 940 and Landlord and Tenant agree to
amend the Lease by adding Paragraph 68 to the Lease as hereinafter provided:

                 68.      Ninth Floor Space.

                          68.1    Landlord hereby leases to Tenant, and Tenant
                 hereby hires and takes from Landlord, approximately 1,697
                 rentable square feet on the ninth floor of the Centerpointe II
                 Building more fully described on the floor plan annexed to
                 this Fourth Amendment as Exhibit A, which shall herein be
                 deemed as the "Suite 940." Landlord shall make available Suite
                 940 to Tenant for Tenant Work on July 1, 1995.  All of the
                 terms and conditions of the Lease applicable to the Premises
                 shall apply to Suite 940, except as set forth below in this
                 Article.

                          68.2.1  Suite 940 will be delivered to Tenant in its
                 "as is "as built" condition and state of repair.  Any mixtures
                 not removed by the prior tenant shall be left in place and not
                 removed by Landlord.  Tenant shall perform Suite 940 Tenant's
                 Work (which term shall mean the provision of materials,
                 components, labor and services encompassed within the work
                 described on Exhibit B to this Fourth Amendment) (i) at
                 Tenant's sole

                 cost, except as provided in Paragraph 68.2.2, and (H) in
                 accordance with the Tenant Design and Construction Process set
                 forth on Exhibit "C" to the Lease and otherwise in accordance
                 with all relevant provisions of the Lease.  To the extent
                 required by law, Landlord will comply with the requirements of
                 the ADA applicable to the Core Elements of Centerpointe 11
                 which may arise because of the performance of Suite 940
                 Tenant's Work and Tenant shall comply with all other ADA
                 requirements respecting Suite 940, including those
                 requirements arising from Suite 940 Tenant's Work.

                          68.2.2  For purposes of Suite 940, the Concession
                 Fund shall equal Seven Dollars ($7.00) per rentable square
                 foot.  All other provisions in the Lease governing the
                 Concession Fund shall apply to Suite 940.

                          68.3    The Term of the Lease shall commence as to
                 Suite 940 on July 1, 1995 ("Suite 940 Lease Commencement
                 Date").  The Term of Lease as to Suite 940 shall expire on the
                 date which is four (4) years after the Suite 940 Rent
                 Commencement Date.

                          68.4    Base Rent payable for Suite 940 shall be
                 fifteen dollars and sixty cents ($15.60) per rentable square
                 foot, net of Electricity Costs, and subject to adjustment as
                 described in article 6.4. Base Rent for Suite 940 shall be
                 payable as provided in Section 6.1.1. Tenant's obligation to
                 pay Rent for Suite 940 shall commence on the earlier of (i)
                 August 1, 1995 or 00 substantial completion of Suite 940
                 Tenant's Work ("Suite 940 Rent Commencement Date").  All other
                 obligations of Tenant pertaining to Suite 940 under the Lease
                 shall commence on the date of this Fourth Amendment.  If the
                 Suite 940 Rent Commencement Date is other than the first day
                 of a month, Base Rent for Suite 940 due from the Suite 940
                 Rent Commencement Date until the first day of the following
                 month shall be prorated and payable on the Suite 940 Rent
                 Commencement Date.

                          68.5    After the Suite 940 Rent Commencement Date,
                          Tenant's Centerpointe H Proportionate Share shall be
                          increase by an amount equal to the percentage derived
                          by dividing the rentable square footage of Suite 940
                          by 204,481.  Therefore, after the Suite

                          940 Rent Commencement, Tenant's Centerpointe H
                          Proportionate Share shall equal 32.23%.

                          68.6 Except as modified by this Fourth Amendment, the
                          Lease shall otherwise remain in full force and
                          effect.


                 IN WITNESS WHEREOF, and intending to be legally bound hereby,
the parties hereto have executed this Fourth Amendment to Lease on the date on
the date first set forth herein.

                                  LANDLORD:

                                  JOSHUA Realty CORPORATION,
                                  a Delaware corporation

                                  By: /s/    Dan Coughlan
                                      ------------------------
                                      Name:  Dan Coughlan
                                      Title: V.P.


                                  TENANT:

                                  AMERICAN MANAGEMENT SYSTEMS, INC.,
                                  a Delaware Corporation

                                  By: /s/    Frank A. Nicolai
                                      ------------------------
                                      Name:  Frank A. Nicolai
                                      Title: EVP, Secretary &
                                      Treasurer

                     FIFTH AMENDMENT TO AGREEMENT OF LEASE
                     BETWEEN JOSHUA REALTY CORPORATION AND
                       AMERICAN MANAGEMENT SYSTEMS, INC.

                 This Fifth Amendment to Agreement of Lease is made this 27th
day of December, 1995, between JOSHUA REALTY CORPORATION, a Delaware
corporation (general partner and sole remaining partner of Faircenter Limited
Partnership, a Delaware limited partnership) (hereinafter referred to as
"Landlord"), and AMERICAN MANAGEMENT SYSTEMS, INC., a Delaware corporation
(hereinafter referred to as "Tenant").

                                   BACKGROUND

                 A.       Landlord and Tenant entered into a certain Agreement
of Lease dated August 10, 1992, as amended by a First Amendment to Agreement of
Lease dated May 24, 1993, by a Second Amendment to Agreement of Lease dated
March 18, 1994, by a Third Amendment to Agreement of Lease Dated June 5, 1995
and by a Fourth Amendment to Agreement of Lease Dated June 18, 1995 (as
amended, the "Lease").  Capitalized terms used in this Fifth Amendment and not
defined shall have the meanings ascribed to them under the Lease.

                 B.       Landlord and Tenant desire that Tenant lease from
Landlord approximately 3,687 rentable square feet on the ninth floor of the
Centerpointe II Building known as suite 960 and Landlord and Tenant agree to
amend the Lease by adding Paragraph 69 to the Lease as hereinafter provided:

                          69.     Ninth Floor Space.

                                  69.1     Landlord hereby leases to Tenant,
                          and Tenant hereby hires and takes from Landlord,
                          approximately 3,687 rentable square feet on the ninth
                          floor of the Centerpointe II Building more fully
                          described on the floor plan annexed to this Fifth
                          Amendment as Exhibit A, which shall herein be deemed
                          as the "Suite 960." Landlord shall make available
                          Suite 960 to Tenant for Tenant Work on January 1,
                          1996.  All of the terms and conditions of the Lease
                          applicable to the Premises shall apply to Suite 960,
                          except as set forth below in this Article.

                           69.2.1          Suite 960 will be delivered to
                          Tenant in its "as is", "as built" condition and state
                          of repair.  Any fixtures not removed by the prior
                          tenant shall be left in place and not removed by
                          Landlord.  Tenant shall perform Suite 960's

                          Tenant's Work (which term shall mean the provision of
                          materials, components, labor and services encompassed
                          within the work described on Exhibit B to this Fifth
                          Amendment) (i) at Tenant's sole cost, except as
                          provided in Paragraph 69.2.2, and (ii) in accordance
                          with the Tenant Design and Construction Process set
                          forth on Exhibit "C" to the Lease and otherwise in
                          accordance with all relevant provisions of the Lease.
                          To the extent required by law, Landlord will comply
                          with the requirements of the ADA applicable to the
                          Core Elements of Centerpointe II which may arise
                          because of the performance of Suite 960 Tenant's Work
                          and Tenant shall comply with all other ADA
                          requirements respecting Suite 960, including those
                          requirements arising from Suite 960 Tenant's Work.

                                  69.2.2   For purposes of Suite 960, the
                          Concession Fund shall equal Zero Dollars ($0.00) per
                          rentable square foot.

                                  69.3     The Term of the Lease shall commence
                          as to Suite 960 on January 1, 1996 ("Suite 960 Lease
                          Commencement Date").  The Term of Lease as to Suite
                          960 shall expire on the date which is two (2) years
                          after the Suite 960 Rent Commencement Date.

                                  69.4     Base Rent payable for Suite 960
                          shall be twenty-two dollars and thirty, cents
                          ($22.30) per rentable square foot, net of Electricity
                          Costs, and subject to adjustment as described in
                          article 6.4.  Base Rent for Suite 960 shall be
                          payable as provided in Section 6.1.1.  Tenant's
                          obligation to pay Rent for Suite 960 shall commence
                          on the earlier of (i) February 15, 1995 or (ii)
                          substantial completion of Suite 960 Tenant's Work
                          ("Suite 960 Rent Commencement Date").  All other
                          obligations of Tenant pertaining to Suite 960 under
                          the Lease shall commence on the date of this Fourth
                          Amendment.  If the Suite 960 Rent Commencement Date
                          is other than the first day of a month, Base Rent for
                          Suite 960 due from the Suite 960 Rent Commencement
                          Date until the first day of the following month shall
                          be prorated and payable on the Suite 960 Rent
                          Commencement Date.

                                  69.5     After Suite 960 Rent Commencement
                          Date, Tenant's Centerpointe II Proportionate Share
                          shall be increase by an amount equal to the
                          percentage derived by dividing the rentable square
                          footage of

                          Suite 960 by 204,481.  Therefore, after the Suite 960
                          Rent Commencement, Tenant's Centerpointe II
                          Proportionate Share shall equal 32.25%.

                                  69.6     If the Term of the Lease as to Suite
                          960 has not commenced by April 1, 1996, either party,
                          by written notice to the other given at any time
                          thereafter, but in all events prior to the Suite 960
                          Commencement Date, may terminate this Fifth
                          Amendment, in which event neither party shall have
                          any further rights or obligations under this Fifth
                          Amendment.

                                  69.7     Except as modified by this Fifth
                          Amendment, the Lease shall otherwise remain in full
                          force and effect.

                                  69.8     Notwithstanding anything contained
                          in this Fifth Amendment, if Landlord is unable to
                          make Suite 960 available to tenant by January 1, 1996
                          as a result of a hold over of the existing tenant of
                          Suite 960, then:  (i) the Suite 960 Lease
                          Commencement Date shall not be January 1, 1996 but
                          shall be such later date as Landlord shall advise
                          Tenant in writing following the vacation of Suite 960
                          by the current tenant, (ii) the validity of this
                          Fifth Amendment and the obligations of Tenant under
                          the Fifth Amendment shall not be affected by such
                          failure to deliver possession of Suite 960, except
                          that the Suite 960 Rent Commencement Date shall
                          instead be the earlier of (A) forty-five days after
                          the Suite 960 Lease Commencement Date or (B)
                          substantial completion of the Suite 960 Tenant's
                          Work, and (iii) Tenant shall have no claim against
                          Landlord arising out of Landlord's failure or
                          inability to deliver possession of Suite 960 on the
                          date originally fixed therefor.

                 IN WITNESS WHEREOF, and intending to be legally bound hereby,
the parties hereto have executed this Fifth Amendment to Lease on the date on
the date first set forth herein.

                                  LANDLORD:

                                  JOSHUA REALTY CORPORATION,
                                  a Delaware corporation

                                  By: /s/ Dan Coughlan
                                      ----------------------------------
                                      Name:  Dan Coughlan
                                      Title:


                                  TENANT:

                                  AMERICAN MANAGEMENT SYSTEMS, INC.,
                                  a Delaware Corporation

                                  By: /s/ Frank A. Nicolai
                                      ----------------------------------
                                      Name:   Frank A. Nicolai
                                      Title:  EVP, Secretary & Treasurer

                     SIXTH AMENDMENT TO AGREEMENT OF LEASE
                     BETWEEN JOSHUA REALTY CORPORATION AND
                       AMERICAN MANAGEMENT SYSTEMS, INC.

                 This Sixth Amendment to Agreement of Lease is made this _____
day of ________, 1996, between JOSHUA REALTY CORPORATION, a Delaware
corporation (general partner and sole remaining partner of Faircenter Limited
Partnership, a Delaware limited partnership) (hereinafter referred to as
"Landlord"), and AMERICAN MANAGEMENT SYSTEMS, INC., a Delaware corporation
(hereinafter referred to as "Tenant").

                              B A C K G R 0 U N D:

                 A.       Landlord and Tenant entered into a certain Agreement
of Lease dated August 10, 1992, as amended by a First Amendment to Agreement of
Lease dated May 24, 1993, by a Second Amendment to Agreement of Lease dated
March 18, 1994, by a Third Amendment to Agreement of Lease dated June 5, 1995,
by a Fourth Amendment to Agreement of Lease dated June 18, 1995 and by a Fifth
Amendment to Agreement of Lease dated December 27, 1995 (as amended, the
"Lease").  Capitalized terms used in this Sixth Amendment and not defined shall
have the meanings ascribed to them under the Lease.

                 B.       Landlord and Tenant desire that Tenant lease from
Landlord approximately 28,359 additional rentable square feet on the tenth and
eleventh floors of the Centerpointe II Building and Landlord and Tenant agree
to amend the Lease by adding Article 70 to the Lease as hereinafter provided:

                          70.     Tenth/Eleventh Floor Space.

                                  70.1     Landlord hereby leases to Tenant,
                          and Tenant hereby hires and takes from Landlord,
                          approximately 28,359 rentable square feet on the
                          tenth and eleventh floors of the Centerpointe II
                          Building, as more fully described on the floor plan
                          annexed to this Amendment as Exhibit A, which shall
                          herein be defined as the "Tenth/Eleventh Floor
                          Space." All of the terms and conditions of the Lease
                          applicable to the Premises shall apply to such
                          Tenth/Eleventh Floor Space, except as set forth below
                          in this Article.

                                  70.2.1   The Tenth/Eleventh Floor Space will
                          be delivered to Tenant in its "as is", "as built"
                          condition and state of repair.  Any fixtures not
                          removed by the prior tenant shall be left in place

                          and not removed by Landlord.  Tenant shall perform
                          all work necessary to install any tenant improvements
                          or otherwise necessary to prepare the Tenth/Eleventh
                          Floor Space (i) at Tenant's sole cost, except as
                          provided in Paragraph 70.2.2, and (ii) in accordance
                          with the Tenant Design and Construction Process set
                          forth on Exhibit 'IC" to the Lease and otherwise in
                          accordance with all relevant provisions of the Lease.
                          To the extent required by law, Landlord will comply
                          with the requirements of the ADA applicable to the
                          Core Elements of Centerpointe II which may arise
                          because of the performance of the Tenth/Eleventh
                          Floor Tenant's Work and Tenant shall comply with all
                          other ADA requirements respecting the Tenth/Eleventh
                          Floor Space, including those requirements arising
                          from the Tenth/Eleventh Floor Tenant's Work.

                                  70.2.2   For purposes of the Tenth/Eleventh
                          Floor Space, the Concession Fund shall equal Ten
                          Dollars ($10.00) per rentable square foot.  All other
                          provisions in the Lease governing the Concession Fund
                          shall apply to-the Tenth/Eleventh Floor Space.

                                  70.3     The Term of the Lease shall commence
                          as to the Tenth/Eleventh Floor Space on March 15,
                          1997 ("Tenth/Eleventh Floor Space Lease Commencement
                          Date"); provided, that if Landlord is unable to
                          deliver the Tenth/Eleventh Floor Space to Tenant by
                          March 15, 1997 for any reason whatever, including
                          without limitation by reason of the holding over of
                          any tenant, then the Tenth/Eleventh Floor Space Lease
                          Commencement Date shall be delayed until such time as
                          Landlord delivers such space to Tenant and Landlord
                          will have no liability to Tenant in any event for any
                          such delay.  The Term of the Lease as to the
                          Tenth/Eleventh Floor Space shall expire on the
                          Termination Date.  Notwithstanding anything contained
                          in this Amendment, if for any reason Landlord has not
                          delivered the Tenth/Eleventh Floor Space to Tenant by
                          July 1, 1997, then upon written notice from Tenant to
                          Landlord given at any time after July 1, 1997 and
                          prior to the date Landlord delivers the
                          Tenth/Eleventh Floor Space to Tenant, as its sole and
                          exclusive remedy, Tenant may terminate this Sixth
                          Amendment, whereupon this Amendment shall be null and
                          void and neither party

                          shall have any further rights or obligations under
                          this Sixth Amendment.

                                  70.4     Base Rent payable for the
                          Tenth/Eleventh Floor Space shall be Twenty-One and
                          50/100 Dollars ($21.50) per rentable square foot,
                          inclusive of Electricity Costs, and subject to
                          adjustment as described in Article 6.3. Base Rent for
                          the Tenth/Eleventh Floor Space shall be payable as
                          provided in Section 6.1.1. Tenant's obligation to pay
                          Rent for the Tenth/Eleventh Floor Space and all other
                          obligations of Tenant pertaining to the
                          Tenth/Eleventh Floor Space under the Lease shall
                          commence on the Tenth/Eleventh Floor Space Lease
                          Commencement Date.  If the Tenth/Eleventh Floor Space
                          Lease Commencement Date is other than the first day
                          of a month, Base Rent for the Tenth/Eleventh Floor
                          Space due from the Tenth/Eleventh Floor Space Lease
                          Commencement Date until the first day of the
                          following month shall be prorated and payable on the
                          Tenth/Eleventh Floor Lease Commencement Date.

                                  70.5     After the Tenth/Eleventh Floor Space
                          Lease Commencement Date, Tenant's Centerpointe II
                          Proportionate Share shall be increased by an amount
                          equal to the percentage derived by dividing the
                          rentable square footage of the Tenth/Eleventh Floor
                          Space by 204,481.  Therefore, after the
                          Tenth/Eleventh Floor Space Lease Commencement Date,
                          Tenant's Centerpointe II Proportionate Share shall
                          equal 47.9%.

                                  70.6     Except as modified by this Sixth
                          Amendment, the Lease shall otherwise remain in full
                          force and effect.

                 IN WITNESS WHEREOF, and intending to be legally bound hereby,
the parties hereto have executed this Sixth Amendment to Lease on the date
first set forth herein.

                                  LANDLORD:

                                  JOSHUA REALTY CORPORATION,
                                  a Delaware corporation

                                  By:
                                       -----------------------------
                                       Name:
                                       Title:


                                  TENANT:

                                  AMERICAN MANAGEMENT SYSTEMS, INC.,
                                  a Delaware corporation

                                  By:  /s/    Frank A. Nicolai
                                       -----------------------------
                                       Name:  Frank A. Nicolai
                                       Title: EVP, Sec. & Treasurer

[THE FOLLOWING PAGES INCLUDED AS EXHIBITS A AND B, FLOOR PLANS OF THE
PREMISES.]

                    SEVENTH AMENDMENT TO AGREEMENT OF LEASE
                     BETWEEN JOSHUA REALTY CORPORATION AND
                       AMERICAN MANAGEMENT SYSTEMS, INC.

                 This Seventh Amendment to Agreement of Lease is made as of
this 22nd day of July, 1996, between JOSHUA REALTY CORPORATION, a Delaware
corporation (general partner and sole remaining partner of Faircenter Limited
Partnership, a Delaware limited partnership) (hereinafter referred to as
"Landlord"), and AMERICAN MANAGEMENT SYSTEMS, INC., a Delaware corporation
(hereinafter referred to as "Tenant").

                              B A C K G R O U N D:

                 A.       Landlord and Tenant entered into a certain Agreement
of Lease dated August 10, 1992, as amended by a First Amendment to Agreement of
Lease dated May 24, 1993, by a Second Amendment to Agreement of Lease dated
March 18, 1994, by a Third Amendment to Agreement of Lease dated June 5, 1995,
by a Fourth Amendment to Agreement of Lease dated June 18, 1995, by a Fifth
Amendment to Agreement of Lease dated December 27, 1995 and by a Sixth
Amendment to Agreement of Lease (undated) (as amended, the "Lease").
Capitalized terms used in this Seventh Amendment and not defined shall have the
meanings ascribed to them under the Lease.

                 B.       Landlord and Tenant desire that Tenant lease from
Landlord approximately 1,829 additional rentable square feet on the first floor
of the Centerpointe II Building and Landlord and Tenant agree to amend the
Lease by adding Article 71 to the Lease as hereinafter provided:

                 71.       First Floor Space.

                           71.1   Landlord hereby leases to Tenant, and Tenant
                 hereby hires and takes from Landlord, approximately 1,829
                 rentable square feet on the first floor of the Centerpointe II
                 Building, as more fully described on the floor plan annexed to
                 this Amendment as Exhibit Al which shall herein be defined as
                 the "First Floor Space." All of the terms and conditions of
                 the Lease applicable to the Premises shall apply to such First
                 Floor Space, except as set forth below in this Article.

                           71.2.1          The First Floor Space will be
                 delivered to Tenant in its "as is" , "as built" condition and
                 state of repair.  Any fixtures not removed by the prior tenant
                 shall be left in place and not removed by

                 Landlord.  Tenant shall perform all work (the "First Floor
                 Tenant's Work") necessary to install any tenant improvements
                 or otherwise necessary to prepare the First Floor Space (i) at
                 Tenant's sole cost and (ii) in accordance with the Tenant
                 Design and Construction Process set forth on Exhibit 'IC" to
                 the Lease and otherwise in accordance with all relevant
                 provisions of the Lease.  To the extent required by law,
                 Landlord will comply with the requirements of the ADA
                 applicable to the Core Elements of Centerpointe II which may
                 arise because of the performance of the First Floor Tenant's
                 Work and Tenant shall comply with all other ADA requirements
                 respecting the First Floor Space, including those requirements
                 arising from the First Floor Tenant's Work.

                           71.2.2 For purposes of the First Floor Space, there
                 shall be no Concession Fund.

                           71.3   The Term of the Lease shall commence as to
                 the First Floor Space on July 22, 1996 ("First Floor Space
                 Lease Commencement Date").  The Term of the Lease as to the
                 First Floor Space shall expire on December 31, 2000.

                           71.4   Base Rent payable for the First Floor Space
                 shall be Nineteen Dollars ($19.00) per rentable square foot,
                 inclusive of Electricity Costs, and subject to adjustment as
                 described in Article 6.3. Base Rent for the First Floor Space
                 shall be payable as provided in Section 6.1.1. Tenant's
                 obligation to pay Rent for the First Floor Space shall
                 commence on August 1, 1996.

                           71.5   After the First Floor Space Lease
                 Commencement Date, Tenant's Centerpointe II Proportionate
                 Share shall be increased by an amount equal to the percentage
                 derived by dividing the rentable square footage of the First
                 Floor Space by 204,481.  Therefore, after the First Floor
                 Space Lease Commencement Date, Tenant's Centerpointe II
                 Proportionate Share shall equal 48.79%.

                           71.6   Except as modified by this Seventh Amendment,
                 the Lease shall otherwise remain in full force and effect.

                 IN WITNESS WHEREOF, and intending to be legally bound hereby,
the parties hereto have executed this Seventh Amendment to Lease as of the date
first set forth herein.

                                  LANDLORD:

                                  JOSHUA REALTY CORPORATION,
                                  a Delaware corporation

                                  By: /s/    Dan Coughlan
                                      ------------------------------
                                      Name:  Daniel Coughlan
                                      Title:


                                  TENANT:

                                  AMERICAN MANAGEMENT SYSTEMS, INC.,
                                  a Delaware corporation

                                  By: /s/    Frank A. Nicolai
                                      ------------------------------
                                      Name:  Frank A. Nicolai
                                      Title: Executive Vice President

[THE FOLLOWING PAGE INCLUDED AS EXHIBIT A FLOOR PLAN OF THE PREMISES.]

                     EIGHTH AMENDMENT TO AGREEMENT OF LEASE
                     BETWEEN JOSHUA REALTY CORPORATION AND
                       AMERICAN MANAGEMENT SYSTEMS, INC.

         This Eighth Amendment to Agreement of Lease is made as of this 12th
day of February, 1997 between JOSHUA REALTY CORPORATION, a Delaware corporation
(general partner and sole remaining partner of Faircenter Limited Partnership,
a Delaware limited partnership) (hereinafter referred to as "Landlord"),
AMERICAN MANAGEMENT SYSTEMS, INC., a Delaware corporation (hereinafter referred
to as "Tenant"), and QUALITY SYSTEMS, INC., a Virginia corporation ("QSI").

                              B A C K G R O U N D:

         A.      Landlord and Tenant entered into a certain Agreement of Lease
dated August 10, 1992, as amended by a First Amendment to Agreement of Lease
dated May 24, 1993, by a Second Amendment to Agreement of Lease dated March 18,
1994, by a Third Amendment to Agreement of Lease dated June 5, 1995, by a
Fourth Amendment to Agreement of Lease dated June 18, 1995, by a Fifth
Amendment to Agreement of Lease dated December 27, 1995, by a Sixth Amendment
to Agreement of Lease (undated) and by a Seventh Amendment to Agreement of
Lease dated July 22, 1996 (as amended, the "Lease").  Capitalized terms used in
this Eighth Amendment and not defined shall have the meanings ascribed to them
under the Lease.

         B.      Pursuant to the Sixth Amendment to Agreement of Lease dated
(undated) (the "Sixth Amendment"), Landlord and Tenant agreed that Tenant lease
from Landlord approximately 28,359 additional rentable square feet on the tenth
and eleventh floors of Centerpointe II Building, which space is currently
occupied by QSI and defined in the Sixth Amendment, Section 70.1 as the
"Tenth/Eleventh Floor Space."

         C.      Pursuant to the Sixth Amendment, the Term of the Lease for the
Tenth/Eleventh Floor Space was to commence March 15, 1997, which date is the
day following the expiration of the lease between Landlord and QSI dated
December 21, 1989 (the "QSI Lease").

         D.      Pursuant to a Termination Agreement of even date herewith
between Landlord and QSI, Landlord and QSI have agreed to terminate the QSI
Lease early, on February 17, 1997.

         E.      Landlord and Tenant desire that Tenant lease from Landlord the
Tenth/Eleventh Floor Space on February 18, 1997, which date is approximately
one (1) month earlier than the

Tenth/Eleventh Floor Lease Commencement Date set forth in Section 70.3 of the
Sixth Amendment.

         NOW, THEREFORE, for good and valuable consideration, including the
mutual promises, covenants and agreements herein contained, the parties hereto
mutually covenant and agree that the Lease is hereby amended as follows:

         1.      Term.  The dated "March 15, 1997" set forth in the second and
fifth lines of Section 70.3 of the Sixth Amendment is hereby deleted in both
instances, and substituted in each instance in lieu thereof is the date
"February 18, 1997."

         2.      Base Rent.  Notwithstanding anything to the contrary set forth
in Section 70.4 of the Sixth Amendment, Base Rent during any portion of the
Term of the Lease for the Tenth/Eleventh Floor Space prior to March 15, 1997
shall equal Seventeen and 50/100 Dollars ($17.50) per rentable square foot of
the Tenth/Eleventh Floor Space per annum, inclusive of Electricity Costs, and
not subject to adjustment as described in Section 6.3 of the Lease.  Commencing
March 15, 1997, Base Rent for the Tenth/Eleventh Floor Space shall be payable
in accordance with Section 70.4 of the Sixth Amendment.

         3.      Effect.  Except as modified by this Eighth Amendment, the
Lease shall otherwise remain in full force and effect.


         IN WITNESS WHEREOF, and intending to be legally bound hereby, the
parties hereto have executed this Eighth Amendment to Lease as of the date
first set forth herein.

                                  LANDLORD:

                                  JOSHUA REALTY CORPORATION,
                                  a Delaware corporation

                                  By:  /s/    Dan Coughlan
                                       -----------------------------
                                       Name:  Daniel P. Coughlan
                                       Title:


                                  TENANT:

                                  AMERICAN MANAGEMENT SYSTEMS, INC.,
                                  a Delaware corporation

                                  By:  /s/    Frank A. Nicolai
                                       -----------------------------
                                       Name:  Frank A. Nicolai
                                       Title:


                                  QSI:

                                  QUALITY SYSTEMS, INC.,
                                  a Virginia corporation

                                  By:  /s/    Dan O'Neill
                                       -----------------------------
                                       Name:  Dan O'Neill
                                       Title: VP, Finance & Admin.

                     NINTH AMENDMENT TO AGREEMENT OF LEASE
                     BETWEEN JOSHUA REALTY CORPORATION AND
                       AMERICAN MANAGEMENT SYSTEMS, INC.

         This Ninth Amendment to Agreement of Lease is made as of this 4th day
of March, 1997 between JOSHUA REALTY CORPORATION, a Delaware corporation
(general partner and sole remaining partner of Faircenter Limited Partnership,
a Delaware limited partnership) (hereinafter referred to as "Landlord") and
AMERICAN MANAGEMENT SYSTEMS, INC., a Delaware corporation (hereinafter referred
to as "Tenant").

                              B A C K G R O U N D:

         A.      Landlord and Tenant entered into a certain Agreement of Lease
dated August 10, 1992, as amended by a First Amendment to Agreement of Lease
dated May 24, 1993, by a Second Amendment to Agreement of Lease dated March 18,
1994, by a Third Amendment to Agreement of Lease dated June 5, 1995, by a
Fourth Amendment to Agreement of Lease dated June 18, 1995, by a Fifth
Amendment to Agreement of Lease dated December 27, 1995, by a Sixth Amendment
to Agreement of Lease (undated) and by a Seventh Amendment to Agreement of
Lease dated July 22, 1996 and by an Eighth Amendment to Agreement of Lease
dated as of February 12, 1997 (as amended, the "Lease").  Capitalized terms
used in this Ninth Amendment and not defined shall have the meanings ascribed
to them under the Lease.

         B.      Landlord and Tenant desire that Tenant lease from Landlord,
Suite 900, containing approximately 5,664 additional rentable square feet on
the ninth floor of the Counterpointe II Building and Landlord and Tenant agree
to amend the Lease by adding Article 72 to the Lease as hereinafter provided:

         72.     Suite 900 Space.

                          72.1  Landlord hereby leases to Tenant, and Tenant
                 hereby hires and takes from Landlord, approximately 5,664
                 rentable square feet on the ninth floor of the Centerpointe II
                 Building, as more fully described on the floor plan annexed to
                 this Amendment as Exhibit A, which shall herein be defined as
                 the "Suite 900 Space."  All of the terms and conditions of the
                 Lease applicable to the Premises shall apply to such Suite 900
                 Space, except as set forth below in this Article.

                          72.2.1  The Ninth Floor Space will be delivered to
                 Tenant in its "as is", "as built" condition and state of

                 repair.  Any fixtures not removed by the prior tenant shall be
                 left in place and not removed by Landlord.  Tenant shall
                 perform all work (the "Suite 900 Tenant's Word") necessary to
                 prepare the Suite 900 Space (i) at Tenant's sole cost and (ii)
                 in accordance with the Tenant Design and Construction Process
                 set forth on Exhibit "C" to the Lease and otherwise in
                 accordance with all relevant provisions of the Lease.  To the
                 extent required by law, Landlord will comply with the
                 requirements of the ADA applicable to the Core Elements of
                 Centerpointe II which may arise because of the performance of
                 the Suite 900 Tenant's Work and Tenant shall comply with all
                 other ADA requirements respecting the Suite 900 Space,
                 including those requirements arising from the Suite 900
                 Tenant's Work.

                          72.2.2  For purposes of the Suite 900 Space, there
                 shall be no Concession Fund.

                          72.3  The term of the Lease shall commence as to the
                 Suite 900 Space on May 10, 1997 ("Suite 900 Space Lease
                 Commencement Date").  The Term of the Lease as to the Suite
                 900 Space shall expire on May 31, 2002.

                          72.4  Base Rent payable for the Suite 900 Space shall
                 be Nineteen and 50/100 Dollars ($19.50) per rentable square
                 foot, inclusive of Electricity Costs, and subject to
                 adjustment as described in Article 6.3.  Base Rent for the
                 Suite 900 Space shall be payable as provided in Section 6.1.1.
                 Tenant's obligation to pay Rent for the Suite 900 Space shall
                 commence on May 10, 1997.

                          72.5  After the Suite 900 Space Lease Commencement
                 Date, Tenant's Centerpointe II Proportionate Share shall be
                 increased by an amount equal to the percentage derived by
                 dividing the rentable square footage of the Suite 900 Space by
                 204,481.  Therefore, after the Suite 900 Space Lease
                 Commencement Date, Tenant's Counterpointe II Proportionate
                 Share shall equal 51.56%.

                          72.6  Except as modified by this Ninth Amendment, the
                 Lease shall otherwise remain in full force and effect.

         IN WITNESS WHEREOF, and intending to be legally bound hereby, the
parties hereto have executed this Ninth Amendment to Lease as of the date first
set forth herein.

                                  LANDLORD:

                                  JOSHUA REALTY CORPORATION,
                                  a Delaware corporation

                                  By:  /s/    Dan Coughlan
                                       -------------------------------
                                       Name:
                                       Title:


                                  TENANT:

                                  AMERICAN MANAGEMENT SYSTEMS, INC.,
                                  a Delaware corporation

                                  By:  /s/    Frank A. Nicolai
                                       -------------------------------
                                       Name:  Frank A. Nicolai
                                       Title: Executive Vice President

[THE FOLLOWING PAGE INCLUDED AS AN EXHIBIT A FLOOR PLAN OF THE PREMISES.]

                             TERMINATION AGREEMENT

         This TERMINATION AGREEMENT (this "Agreement"), made this 11th day of
February, 1997 between JOSHUA REALTY CORPORATION, a Delaware corporation
(general partner and sole remaining partner of Faircenter Limited Partnership,
a Delaware limited partnership) (the "Landlord"), and QUALITY SYSTEMS, INC., a
Virginia corporation (the "Tenant"), and VITRO CORPORATION, a Delaware
corporation (the "Guarantor").

                              W I T N E S S E T H:

         WHEREAS, by an Office Building Lease dated December 2, 1989, by and
between Landlord and Tenant (the "Lease"), Landlord leased to Tenant and Tenant
leased from Landlord all of that real property, situate and lying in Fairfax,
Virginia, which is described therein (the "Premises") (Capitalized terms used
herein and not otherwise defined shall have the meanings ascribed to them in
the Lease.); and

         WHEREAS, as of the date hereof, the Term of the Lease has not expired
or otherwise terminated, and the Lease remains in full force and effect; and

         WHEREAS, Landlord and Tenant desire to terminate the Lease, upon the
terms and subject to the conditions which are hereinafter set forth.

         NOW, THEREFORE, FOR AND IN CONSIDERATION of the mutual entry into this
Agreement by the parties hereto, and for other good and valuable consideration,
the receipt and adequacy of which are hereby acknowledged, the parties hereto
hereby agree as follows:

Section 1.  Termination of Lease.

         1.1.  Notwithstanding anything contained in the provisions of the
Lease to the contrary, the Term shall end at 11:59 o'clock p.m. on February 17,
1997 (the "Termination Date").  Tenant shall have no right to occupy or use the
Premises thereafter, and shall thereupon immediately surrender possession of
the Premises to Landlord in accordance with the provisions of Section 6.10 of
the Lease.

         1.2.  Termination of the Lease shall not alter or impair any and all
liability of Tenant or Guarantor accruing under the provisions of the Lease at
or before such termination of the Lease (including, by way of example rather
than of limitation, any

liability for Base Annual Rent or Additional Rent accruing at or before such
termination).

Section 2.  Consideration.

         2.1     Consideration.  In consideration of the granting by Landlord
of the early termination of the Lease, Tenant shall pay to Landlord,
simultaneously with the execution of this Agreement, the amount of Twenty-Three
Thousand Eight Hundred Sixty-Nine and 32/100 Dollars ($23,869.32).

         2.2     Attorney's Fees.  Upon presentation of an invoice from
Landlord, Tenant agrees to reimburse Landlord for Landlord's attorney's fees
not to exceed $720.00 incurred in connection with both the termination of this
Lease and the Eighth Amendment to Lease Agreement between Landlord and American
Management Systems, Inc. of even date herewith.

         Section 3. Mutual release.  Provided that each party hereto performs
its obligations under the provisions of this Agreement and except as is
otherwise provided in subsection 1.2 hereof, each party hereto hereby releases
the other party from any and all obligations which the released party may have
to the other under the provisions of the Lease (including, by way of example
rather than of limitation, any and all such obligations which Tenant or
Guarantor may have for the payment of Rent to the Landlord which would have
been due beyond the Termination Date had this Lease not been terminated).

*not to exceed $720.00

         IN WITNESS WHEREOF, each party hereto has caused this Agreement to be
and ensealed on its behalf by its duly authorized representatives, the day and
year first above written.

ATTEST/WITNESS:                   JOSHUA REALTY CORPORATION,
                                  a Delaware corporation


/s/ Raymond L. Owens              By:  /s/    Dan Coughlan
- - ---------------------------            -------------------------------
                                       Name:  Daniel P. Coughland
                                       Title:


ATTEST/WITNESS:                   QUALITY SYSTEMS, INC.,
                                  a Virginia corporation


/s/ [SIG]                         By:  /s/    Dean O'Neill
- - ---------------------------            -------------------------------
                                       Name:  Dean O'Neill
                                       Title: VP Finance & Admin.


ATTEST/WITNESS:                   VITRO CORPORATION


/s/ [SIG]                         By:  /s/    Arthur Rossi
- - ---------------------------            -------------------------------
                                       Name:  Arthur Rossi
                                       Title: Senior Vice President