AGREEMENT AND PLAN OF REORGANIZATION



     THIS AGREEMENT AND PLAN OF REORGANIZATION  ("Agreement") is entered into as
of this 18th day of August,  1997, by and among PUBLIC  STORAGE  PROPERTIES  XI,
INC., a California corporation ("PSP11"), AMERICAN OFFICE PARK PROPERTIES, INC.,
a  California  corporation  ("AOPP")  and PUBLIC  STORAGE,  INC.,  a  California
corporation ("PSI").

     A.  The  parties  intend  that this  Agreement shall  constitute  a Plan of
Reorganization for purposes of Section 368(a)(1)(A) of the Internal Revenue Code
of 1986, as amended (the "Code").  The Plan of  Reorganization  provides for (i)
the  merger  of AOPP  with and  into  PSP11 in  accordance  with the  applicable
provisions  of the General  Corporation  Law of  California  (the "GCLC") and an
Agreement  of Merger  substantially  in the form  attached  hereto as  Exhibit A
("Merger   Agreement")  and  (ii)  the  tax-deferred   like-kind  exchange  (the
"Exchange")  in which  PSP11 will  transfer to PSI the 13  properties  listed on
Exhibit B hereto  (the "PSP11  Exchange  Properties")  and PSI will  transfer to
PSP11  the  11  properties  listed  on  Exhibit  C  hereto  (the  "PSI  Exchange
Properties").

     B.  PSP11, AOPP and PSI believe  that it is in the best  interests  of such
corporations and their  respective  shareholders to enter into and complete this
Agreement  and  they  have  approved   this   Agreement  and  the   transactions
contemplated hereby.

     NOW, THEREFORE, the parties agree as follows:

     1.  Adoption of Plan.  The parties hereby adopt the Plan of  Reorganization
hereinafter set forth.

     2.  The Merger and the Exchange.

         2.1  Completion of the Merger and the Exchange.  At the Effective Time
(as defined  below),  (i) AOPP will be merged with and into PSP11 (the "Merger")
in accordance  with the terms,  conditions  and provisions of this Agreement and
the Merger  Agreement  and (ii) the Exchange will be  consummated  in accordance
with the terms,  conditions and provisions of this  Agreement.  The Merger shall
become  effective at the time at which the Merger  Agreement,  together with the
requisite  Officers'  Certificates  of  PSP11  and  AOPP,  are  filed  with  the
California  Secretary  of State in  accordance  with  the GCLC  (the  "Effective
Time").  PSP11 and AOPP are  sometimes  collectively  referred  to herein as the
"Constituent  Corporations"  and  PSP11,  as the  surviving  corporation  of the
Merger, is sometimes referred to herein as the "Surviving Corporation."

         2.2  Effect of the Merger and Exchange. At the Effective Time:

              2.2.1     Constituent   Corporations.   The  separate  corporate
existence  of AOPP shall cease and the  Surviving  Corporation  shall  thereupon
succeed,  without  other  transfer,  to all the rights and  property of AOPP and



shall be subject to all the debts and  liabilities of AOPP in the same manner as
if the Surviving  Corporation  had itself incurred them; all rights of creditors
and all liens upon the property of each of the Constituent Corporations shall be
preserved  unimpaired,  provided  that such liens upon property of AOPP shall be
limited to the property  affected  thereby  immediately  prior to the  Effective
Time; and any action or proceeding  pending by or against AOPP may be prosecuted
to  judgment,  which  shall bind the  Surviving  Corporation,  or the  Surviving
Corporation may be proceeded against or substituted in its place.

              2.2.2     Articles  and Bylaws.  Except as amended by the Merger
Agreement,  the Articles of Incorporation  and the Bylaws of PSP11, as in effect
at the Effective Time,  shall continue to be the Articles of  Incorporation  and
the Bylaws of the  Surviving  Corporation  until  changed as provided by law and
their respective  provisions;  provided that such Articles of Incorporation  and
Bylaws  may be  amended  and  restated  following  the  Effective  Time in forms
reasonably acceptable to the Surviving Corporation.

              2.2.3    Directors.  The  directors  of the Surviving  Corporation
immediately following the Merger shall be the following:

                       Ronald L. Havner, Jr.
                       Harvey Lenkin
                       Vern O. Curtis
                       James Kropp
                       Jack D. Steele
                       Christopher Weil

                       Such  persons   shall   continue  as  directors  of  the
Surviving  Corporation  until their  successors  are elected  and  qualified  as
provided by law and in accordance with the Articles of Incorporation  and Bylaws
of the Surviving Corporation. If any of the above named individuals is unable to
serve as a director  of the  Surviving  Corporation  at the  Effective  Time,  a
successor will be selected by the remaining above named individuals.

              2.2.4     Officers.  The  executive   officers  of  the  Surviving
Corporation immediately following the Merger shall be the following:

                        Ronald L. Havner, Jr.
                        Mary Jayne Howard

                        Such persons shall continue as officers of the Surviving
Corporation  until their successors are elected and qualified as provided by law
and in accordance with the Articles of Incorporation and Bylaws of the Surviving
Corporation.

              2.2.5     Name.  At the Effective Time, the name of the  Surviving
Corporation shall be changed to "American Office Properties, Inc."

         2.3  Common Stock Series A of PSP11.  Each outstanding  share of Common
Stock Series A ($.01 par value) of PSP11 (the "PSP11  Shares") would continue to
be owned by holders of PSP11 Shares or converted  into the right to receive cash
as follows:

              2.3.1     Cash Election. At the Effective Time, subject to Section
2.7.1  hereof,  each PSP11  Share as to which a cash  election  has been made in
accordance  with the  provisions of Section 2.6 hereof and has not been revoked,
relinquished or lost pursuant to Section 2.6 hereof (the "Cash Election Shares")
shall be converted into and shall represent the right to receive $20.50 in cash.
As soon as practicable after the Effective Time, the registered  holders of Cash
Election  Shares shall be paid the cash to which they are entitled  hereunder in
respect of such Cash Election Shares.

              2.3.2     No Cash Election.   At the Effective Time, subject to
Section 2.12 hereof,  each PSP11 Share (other than Cash Election  Shares) shall
continue to be owned by the holders of the PSP11 Shares.

         2.4  Common Stock Series B and C of PSP11.  Each  outstanding  share of
Common Stock Series B and C ($.01 par value) of PSP11 (the "PSP11 Series B and C
Shares")  would be  converted  into the right to receive cash or PSP11 Shares as
follows:

              2.4.1     Cash  Election.   At  the  Effective  Time,  subject to 
Section 2.7.2  hereof,  each PSP11  Series B and C Share  as  to  which a cash 
election has been made in accordance with the provisions of Section 2.6 hereof
and  has not been revoked, relinquished or lost pursuant to Section 2.6 hereof 
(the "Cash Election  Shares") shall  be  converted  into and shall  represent 
the right to receive $17.71 in cash. As soon as practicable after the Effective
Time, the registered holders of Cash Election Shares shall be paid the cash to 
which they are entitled hereunder in respect of such Cash Election Shares.

              2.4.2     No  Cash  Election.  At the Effective  Time, subject to 
Section 2.12 hereof, each PSP11 Series B and C Share (other than Cash  Election
Shares) shall be converted into 0.8641 PSP11 Shares.  If PSP11 should split or
combine the PSP11 Shares, or pay a stock dividend, such conversion number will
be appropriately adjusted to reflect such action.

         2.5  AOPP Shares.  Each  outstanding  share of Common  Stock  ($.10 par
value) of AOPP (the "AOPP  Shares") would be converted into the right to receive
cash or PSP11 Shares as follows:

              2.5.1     Cash Election. At the Effective Time, subject to Section
2.7.3  hereof,  each  AOPP  Share as to which a cash  election  has been made in
accordance  with the  provisions of Section 2.6 hereof and has not been revoked,
relinquished or lost pursuant to Section 2.6 hereof (the "Cash Election Shares")
shall be converted into and shall represent the right to receive $24.19 in cash.
As soon as practicable after the Effective Time, the registered  holders of Cash
Election  Shares shall be paid the cash to which they are entitled  hereunder in
respect of such Cash Election Shares.

              2.5.2     No  Cash  Election.  At the Effective Time, subject to 
Section 2.12  hereof, each AOPP  Share (other than Cash Election  Shares)  shall
be converted into 1.18 PSP11 Shares.  If PSP11 should split or combine the PSP11
Shares,  or pay a stock dividend,  such conversion  number will be appropriately
adjusted to reflect such number.


         2.6  Procedure  for Cash  Election.  At the time of the  mailing of the
Proxy  Statement and Prospectus  provided for in Section 7.5 hereof,  PSP11 will
send to (i) each  holder  of  record of PSP11  Shares  and PSP11  Series B and C
Shares at the record date for the PSP11 meeting of  shareholders  referred to in
Section 7.2.1 hereof and (ii) each holder of record of AOPP Shares at the record
date for the AOPP meeting of shareholders  referred to in Section 7.2.2 hereof a
cash  election  form (the "Form of  Election")  providing  such  holder with the
option to elect to receive the cash  election  payment  contemplated  by Section
2.3.1,  2.4.1 or 2.5.1 hereof with  respect to such  holder's  shares.  Any such
election to receive  such cash  payment  shall have been  properly  made only if
American  Stock  Transfer & Trust  Company  (the  "Exchange  Agent")  shall have
received at its  designated  office,  by 5:00 p.m.,  New York time,  on the last
business  day  preceding  the day of such  meeting  of  shareholders,  a Form of
Election  properly  completed and accompanied by certificates  for the shares to
which such Form of Election relates (or an appropriate  guarantee of delivery in
a form  and on terms  satisfactory  to  PSP11),  as set  forth  in such  Form of
Election.  Any Form of Election may be revoked by the person submitting the same
to the Exchange  Agent only by written  notice  received by the  Exchange  Agent
prior to 5:00 p.m.,  New York time,  on the last  business day before the day of
the  respective  meeting of  shareholders  referred to in Section 7.2.1 or 7.2.2
hereof. In addition, all Forms of Election shall automatically be revoked if the
Exchange  Agent is notified in writing by the parties hereto that the Merger has
been abandoned.  If a Form of Election is revoked  pursuant to this Section 2.6,
the  certificate or  certificates or any guarantee of delivery in respect of the
PSP11  Shares,  PSP11 Series B and C Shares or AOPP Shares to which such Form of
Election relates shall be promptly returned to the person submitting the same to
the Exchange Agent. The Exchange Agent may determine whether or not elections to
receive cash have been  properly  made or revoked  pursuant to this Section 2.6,
and any such  determination  shall be  conclusive  and binding.  If the Exchange
Agent  determines  that any  election to receive cash was not properly or timely
made,  the PSP11  Shares,  PSP11  Series B and C Shares and AOPP Shares  covered
thereby  shall not be treated as Cash Election  Shares,  and shall be treated in
the Merger as provided in Section  2.3.2,  2.4.2 or 2.5.2  hereof.  The Exchange
Agent  may,  with  the  mutual  agreement  of PSP11  and  AOPP,  establish  such
procedures,  not  inconsistent  with this  Section  2.6, as may be  necessary or
desirable to implement this Section 2.6.

         2.7  Procedure for Proration.

              2.7.1     PSP11 Shares.

                        2.7.1.1 No Proration.  If the aggregate  number of Cash
Election  Shares owned by holders of PSP11 Shares is 20% or less than the number
of  PSP11  Shares  outstanding  as  of  the  record  date  for  the  meeting  of
shareholders of PSP11 referred to in Section 7.2.1, then each such Cash Election
Share shall be converted in the Merger into the right to receive $20.50 in cash.

                        2.7.1.2  Proration.  If the  aggregate  number  of Cash
Election  Shares  owned by holders of PSP11 Shares  exceeds 20%,  then each such
Cash  Election  Share shall be converted in the Merger into the right to receive
cash as follows:  the number of Cash Election  Shares owned by a holder of PSP11
Shares that shall be  converted  into the right to receive  $20.50 in cash shall



equal the number obtained by multiplying (i) 20% of the outstanding PSP11 Shares
by (ii) a fraction of which the  numerator  shall be the number of Cash Election
Shares owned by such holder and the denominator shall be the aggregate number of
Cash Election Shares owned by holders of PSP11 Shares.  The balance of such Cash
Election  Shares shall be treated in accordance  with the  provisions of Section
2.3.2 hereof.  Notwithstanding the foregoing, PSP11, in its sole discretion, may
allow such Cash Election  Shares to receive $20.50 in cash even if the aggregate
number of Cash Election  Shares owned by holders of PSP11 Shares  exceeds 20% of
the number of PSP11 Shares  outstanding as of the record date for the meeting of
shareholders of PSP11 referred to in Section 7.2.1.

              2.7.2     PSP11 Series B and C Shares.

                        2.7.2.1  No Proration.  If the aggregate  number of Cash
Election  Shares  owned by holders of PSP11 Series B and C Shares is 20% or less
than the number of PSP11 Series B and C Shares outstanding as of the record date
for the meeting of shareholders of PSP11 referred to in Section 7.2.1, then each
such Cash  Election  Share  shall be  converted  in the Merger into the right to
receive $17.71 in cash.

                        2.7.2.2   Proration.  If the  aggregate  number  of Cash
Election  Shares  owned by holders of PSP11  Series B and C Shares  exceeds 20%,
then each such Cash  Election  Share shall be  converted  in the Merger into the
right to receive cash as follows:  the number of Cash Election Shares owned by a
holder of PSP11 Series B and C Shares that shall be converted  into the right to
receive $17.71 in cash shall equal the number obtained by multiplying (i) 20% of
the  outstanding  PSP11  Series B and C Shares by (ii) a  fraction  of which the
numerator  shall be the number of Cash Election  Shares owned by such holder and
the denominator  shall be the aggregate  number of Cash Election Shares owned by
holders of PSP11 Series B and C Shares. The balance of such Cash Election Shares
shall be treated in  accordance  with the  provisions  of Section  2.4.2 hereof.
Notwithstanding  the foregoing,  PSP11, in its sole  discretion,  may allow such
Cash Election  Shares to receive $17.71 in cash even if the aggregate  number of
Cash Election Shares owned by holders of PSP11 Series B and C Shares exceeds 20%
of the number of PSP11 Shares  outstanding as of the record date for the meeting
of shareholders of PSP11 referred to in Section 7.2.1.

              2.7.3     AOPP Shares.

                        2.7.3.1   No Proration. If the aggregate  number of Cash
Election  Shares  owned by holders of AOPP Shares is 20% or less than the number
of AOPP Shares outstanding as of the record date for the meeting of shareholders
of AOPP referred to in Section  7.2.2,  then each such Cash Election Share shall
be converted in the Merger into the right to receive $24.19 in cash.

                        2.7.3.2   Proration.  If the  aggregate  number  of Cash
Election Shares owned by holders of AOPP Shares exceeds 20%, then each such Cash
Election  Share shall be  converted in the Merger into the right to receive cash
as follows:  the number of Cash Election Shares owned by a holder of AOPP Shares
that shall be converted into the right to receive $24.19 in cash shall equal the
number obtained by multiplying (i) 20% of the outstanding  AOPP Shares by (ii) a
fraction  of which the  numerator  shall be the number of Cash  Election  Shares
owned by such holder and the denominator  shall be the aggregate  number of Cash



Election  Shares  owned by  holders  of AOPP  Shares.  The  balance of such Cash
Election  Shares shall be treated in accordance  with the  provisions of Section
2.5.2 hereof.  Notwithstanding the foregoing, PSP11, in its sole discretion, may
allow such Cash Election  Shares to receive $24.19 in cash even if the aggregate
number of Cash  Election  Shares owned by holders of AOPP Shares  exceeds 20% of
the number of AOPP Shares  outstanding  as of the record date for the meeting of
shareholders of AOPP referred to in Section 7.2.2.

         2.8  Exchange of Certificates. After the Effective Time, each holder of
a certificate theretofore evidencing outstanding PSP11 Series B and C Shares and
AOPP  Shares  which were  converted  into PSP11  Shares  pursuant  hereto,  upon
surrender  of such  certificate  to the  Exchange  Agent or such other  agent or
agents as shall be appointed by the Surviving Corporation,  shall be entitled to
receive a certificate  representing  the number of whole PSP11 Shares into which
the PSP11 Shares theretofore represented by the certificate so surrendered shall
have been converted as provided in Section 2.3.2 hereof and cash payment in lieu
of fractional  share interests,  if any, as provided in Section 2.11 hereof.  As
soon as  practicable  after the Effective  Time,  the Exchange Agent will send a
notice and a transmittal  form to each holder of record at the Effective Time of
PSP11  Series B and C  Shares  and AOPP  Shares  whose  stock  shall  have  been
converted into PSP11 Shares,  advising such holder of the  effectiveness  of the
Merger and the procedure for  surrendering  to the Exchange  Agent  certificates
evidencing  PSP11  Series  B and C  Shares  and  AOPP  Shares  in  exchange  for
certificates evidencing PSP11 Shares.

         2.9  Status Until Surrendered. Until surrendered as provided in Section
2.8 hereof,  each outstanding  certificate  which,  prior to the Effective Time,
represented  PSP11 Series B and C Shares and AOPP Shares (other than  Dissenting
Shares (as defined below), if any) will be deemed for all corporate  purposes to
evidence  ownership  of the number of whole  PSP11  Shares  into which the PSP11
Series B and C Shares and AOPP Shares evidenced thereby were converted. However,
until such  outstanding  certificates  formerly  evidencing PSP11 Series B and C
Shares and AOPP Shares are so  surrendered,  no  dividend  payable to holders of
record  of  PSP11  Shares  shall  be paid  to the  holders  of such  outstanding
certificates in respect of PSP11 Series B and C Shares and AOPP Shares, but upon
surrender  of such  certificates  by such  holders  there  shall be paid to such
holders the amount of any dividends  (without  interest)  theretofore  paid with
respect to such whole PSP11 Shares as of any record date on or subsequent to the
Effective  Time and the amount of any cash  (without  interest)  payable to such
holder in lieu of fractional share interests pursuant to Section 2.11 hereof.

         2.10 Transfer of Shares.  After the Effective  Time,  there shall be no
further  registration of transfers of PSP11 Series B and C Shares or AOPP Shares
on the respective  corporate  records and, if certificates  formerly  evidencing
such shares are presented to the Surviving Corporation,  they shall be cancelled
and  exchanged  for  certificates  evidencing  PSP11  Shares and cash in lieu of
fractional share interests as herein provided.

         2.11 No Fractional Shares.  Notwithstanding any other term or provision
of this  Agreement,  no fractional  PSP11 Shares and no  certificates  or script
therefor,  or other evidence of ownership thereof, will be issued in the Merger.
In lieu of any such fractional share interests, each holder of AOPP Shares or of
PSP11 Series B and C Shares who would  otherwise be entitled to such  fractional



share will, upon surrender of the certificate  representing such shares, receive
a whole  PSP11  Share  if such  fractional  share  to which  such  holder  would
otherwise have been entitled is .5 of a PSP11 Share or more, and such fractional
share  shall be  disregarded  if it  represents  less than .5 of a PSP11  Share;
provided,  however, that, such fractional share shall not be disregarded if such
fractional  share to which  such  holder  would  otherwise  have  been  entitled
represents  .5 of 1% or more of the total  number of PSP11 Shares such holder is
entitled to receive in the Merger.  In such event,  such holder shall be paid an
amount in cash (without  interest),  rounded to the nearest $.01,  determined by
multiplying (i) the per share closing price on the American Stock Exchange, Inc.
of the PSP11 Shares at the Effective Time by (ii) the factional interest.

         2.12 Dissenting Shares.  PSP11 Shares,  PSP11 Series B and C Shares and
AOPP  Shares held by a holder who has  demanded  and  perfected  his right to an
appraisal of such shares in accordance with Section 1300 et seq. of the GCLC and
who has not  effectively  withdrawn or lost his right to appraisal  ("Dissenting
Shares")  shall not continue to be owned by the holder thereof or converted into
or  represent  the right to receive  cash and/or  PSP11  Shares,  but the holder
thereof  shall be entitled only to such rights as are granted by Section 1300 et
seq. of the GCLC.  Each  holder of  Dissenting  Shares who  becomes  entitled to
payment for PSP11 Shares, PSP11 Series B and C Shares or AOPP Shares pursuant to
these  provisions of the GCLC shall receive payment  therefor from the Surviving
Corporation in accordance therewith. If any holder of PSP11 Shares, PSP11 Series
B and C Shares or AOPP Shares who demands  appraisal in accordance  with Section
1300 et seq.  of the GCLC shall  effectively  withdraw  with the  consent of the
Surviving  Corporation  or lose (through  failure to perfect or  otherwise)  his
right to appraisal with respect to PSP11 Shares,  PSP11 Series B and C Shares or
AOPP  Shares,  such shares shall  continue to be owned by the holder  thereof or
shall automatically be converted into the right to receive PSP11 Shares pursuant
to Section 2.3.2, 2.4.2 or 2.5.2 hereof, as the case may be.

         2.13 Assumption  of  AOPP  Options.   At  the  Effective  Time,  each
outstanding  option to purchase  AOPP Shares (an "AOPP  Option")  granted  under
AOPP's 1997 Stock Option and  Incentive  Plan (the "AOPP Plan") shall be assumed
by PSP11 and, whether vested or unvested,  shall be converted into, and shall be
deemed to  constitute,  an option to acquire,  on the same terms and  conditions
applicable  to the AOPP  Option,  the number of shares of PSP11  Shares that the
holder of the AOPP Option  would have  received in the Merger if the AOPP Option
had been exercised in full immediately prior to the Effective Time, irrespective
of whether the AOPP Option was in fact then exercisable (a "Converted  Option").
The  exercise  price  per share of a  Converted  Option  shall be the  aggregate
exercise  price  of the AOPP  Option  divided  by the  number  of  PSP11  Shares
purchasable upon exercise of the Converted  Option. As soon as practicable after
the  Effective  Time,  PSP11  shall  deliver to each holder of an AOPP Option an
appropriate  notice setting forth the holder's  rights pursuant  thereto.  PSP11
shall  comply with the terms of each AOPP Option and take all  corporate  action
necessary  to reserve  for  issuance  a  sufficient  number of PSP11  Shares for
delivery upon exercise of the Converted Options.

         2.14 Exchange of Deeds.  At the Effective  Time, (i) PSP11 will receive
from escrow deeds for the PSI Exchange Properties and (ii) PSI will receive from



escrow deeds for the PSP11 Exchange  Properties.  PSP11 and PSI acknowledge that
the  PSP11  Exchange  Properties,  and the PSI  Exchange  Properties,  have  the
respective  values  set forth in  Exhibits  B and C  hereto.  PSP11 and PSI also
acknowledge  that the  Exchange is intended to qualify,  as to each of PSP11 and
PSI, for "like-kind exchange" treatment under Section 1031 of the Code.

     3.  Closing.

         3.1  Time and Place of Closing.  If this  Agreement  is approved by the
shareholders of PSP11, a meeting (the "Closing") shall take place as promptly as
practicable thereafter at which the parties will exchange certificates and other
documents as required by this  Agreement.  Such Closing shall take place at such
time and place as PSP11 may designate. The date of the Closing shall be referred
to as the "Closing Date."

         3.2  Execution and Filing of Merger Agreement. At or before the Closing
and after  shareholder  approval by PSP11 and AOPP, PSP11 and AOPP shall execute
and  deliver  the  Merger  Agreement,  together  with  the  requisite  Officers'
Certificates,  for filing with the  California  Secretary  of State.  The Merger
Agreement,  together with the requisite  Officers'  Certificates,  shall be duly
filed with the California Secretary of State in accordance with the GCLC as soon
as practicable following the Closing.

     4.  Representations, Warranties and Agreements of PSP11. PSP11  represents,
warrants and agrees with AOPP and PSI that:

         4.1  Authorization.  Subject  to  approval  of  this  Agreement  by the
shareholders  of PSP11,  (i) the  execution,  delivery and  performance  of this
Agreement  by PSP11 has been  duly  authorized  and  approved  by all  necessary
corporate  action of PSP11  and (ii)  PSP11 has  necessary  corporate  power and
authority to enter into this Agreement, to perform its obligations hereunder and
to complete the transactions contemplated hereby.

         4.2  Organization  and Related  Matters.  PSP11 is a  corporation  duly
organized,  existing  and in  good  standing  under  the  laws of the  State  of
California  with all requisite  corporate  power and authority to own, lease and
operate  its  properties  and to carry on its  business  as and where now owned,
leased,  operated or carried on, as the case may be; and is duly qualified to do
business as a foreign  corporation and is in good standing in each  jurisdiction
in which the  property  owned,  leased or  operated  by it or the  nature of the
business carried on by it requires such  qualification  and where the failure to
so qualify would have a material  adverse  effect on the  business,  properties,
results of  operations or financial  condition of PSP11.  PSP11 has no direct or
indirect  equitable or beneficial  interest in any other  corporation other than
PSCC, Inc.

         4.3  Capital Stock.  The  authorized  capital  stock of PSP11  consists
solely  of (i)  2,828,929  shares  of Common  Stock  Series A ($.01 par  value),
1,819,937  of which were  issued and  outstanding  as of August 18,  1997,  (ii)
184,453  shares of Common  Stock  Series B ($.01 par  value),  all of which were
issued and  outstanding as of August 18, 1997 and (iii) 522,618 shares of Common



Stock Series C ($.01 par value),  all of which were issued and outstanding as of
August 18,  1997  (47,824 of which will be  cancelled  immediately  prior to the
Merger). All of the issued and outstanding shares of capital stock of PSP11 have
been  duly  and  validly   authorized  and  issued,   and  are  fully  paid  and
nonassessable.  There are no options or  agreements to which PSP11 is a party or
by which it is bound  calling for or  requiring  the  issuance of any of PSP11's
capital  stock,  except (A) the PSP11 Common Stock Series B and C is convertible
into PSP11 Shares in accordance with PSP11's Articles of  Incorporation  and (B)
as provided in this Agreement.

         4.4  Consents and Approvals;  No  Violation.  Assuming  approval of the
Merger and of this Agreement by the shareholders of PSP11, neither the execution
and delivery of this Agreement nor the consummation by PSP11 of the transactions
contemplated  hereby  will:  (i)  conflict  with or result in any  breach of any
provision of its Articles of Incorporation or Bylaws;  (ii) require any consent,
waiver, approval, authorization or permit of, or filing with or notification to,
any  governmental  or regulatory  authority,  except (A) in connection  with the
applicable requirements, if any, of the Hart-Scott-Rodino Antitrust Improvements
Act of 1976,  as  amended  (the  "HSR  Act"),  (B)  pursuant  to the  applicable
requirements  of the  federal  securities  laws and the  rules  and  regulations
promulgated  thereunder,  (C) the filing of the Merger  Agreement  and Officers'
Certificates  pursuant to the GCLC and  appropriate  documents with the relevant
authorities of other states in which PSP11 is authorized to do business,  (D) in
connection  with any state or local tax which is  attributable to the beneficial
ownership of PSP11's  real  property,  (E) as may be required by any  applicable
state  securities  or  takeover  laws,  or (F) where the  failure to obtain such
consent,  approval,   authorization  or  permit,  or  to  make  such  filing  or
notification, would not in the aggregate have a material adverse effect on PSP11
or  adversely  affect  the  ability  of PSP11  to  consummate  the  transactions
contemplated  hereby;  (iii) result in a violation or breach of, or constitute a
default (or give rise to any right of termination, cancellation or acceleration)
under any of the terms, conditions or provisions of any note, license, mortgage,
agreement or other  instrument or obligation to which PSP11 is a party or any of
its properties or assets may be bound, except for such violations,  breaches and
defaults  which, in the aggregate,  would not have a material  adverse effect on
PSP11 or adversely  affect the ability of PSP11 to consummate  the  transactions
contemplated hereby; or (iv) assuming the consents, approvals, authorizations or
permits and filings or  notifications  referred to in this  Section 4.4 are duly
and timely  obtained  or made,  violate  any order,  writ,  injunction,  decree,
statute,  rule or regulation  applicable  to PSP11 or its  properties or assets,
except for violations  which would not in the aggregate have a material  adverse
effect on PSP11 or  adversely  affect  the  ability of PSP11 to  consummate  the
transactions contemplated hereby.

         4.5  Litigation.  There is no  litigation,  proceeding or  governmental
investigation which, individually or in the aggregate, is or may be material and
adverse,  pending or, to the  knowledge of PSP11,  threatened  against  PSP11 or
involving any of its properties or assets.

         4.6  SEC Reports.  Since  January 1,  1994,  PSP11 has filed all forms,
reports and  documents  with the  Securities  and  Exchange  Commission  ("SEC")
required to be filed by it pursuant to the federal securities laws and the rules
and regulations promulgated by the SEC thereunder,  all of which complied in all
material  respects with all applicable  requirements  of the federal  securities
laws and such rules and  regulations  (collectively,  the "PSP11 SEC  Reports").



None of the  PSP11 SEC  Reports,  including  without  limitation  any  financial
statements or schedules included therein, at the time filed contained any untrue
statement of a material  fact or omitted to state a material fact required to be
stated therein or necessary in order to make the statements therein, in light of
the circumstances under which they were made, not misleading.

         4.7  Financial  Statements.  The financial  statements  included in the
PSP11 SEC Reports  complied as to form in all material  respects with applicable
accounting  requirements and the published rules and regulations of the SEC with
respect  thereto,  have been  prepared in  accordance  with  generally  accepted
accounting  principles  applied on a basis consistent with prior periods (except
as otherwise noted therein),  and present fairly the financial position of PSP11
as of their  respective  dates,  and the results of  operations of PSP11 for the
periods  presented  therein  (subject,  in the  case  of the  unaudited  interim
financial statements, to normal year-end adjustments).

         4.8  Absence of Certain Changes or Events.  Since January 1, 1997,  the
business of PSP11 has been  carried on only in the ordinary and usual course and
there has not been any  material  adverse  change in its  business,  results  of
operations or financial condition, or any damage or destruction in the nature of
a casualty loss,  whether covered by insurance or not, that would materially and
adversely affect its properties, business or results of operations.

         4.9  S-4 Registration  Statement and  Proxy  Statement  and Prospectus.
None of the information supplied or to be supplied by  PSP11  for  inclusion  or
incorporation  by  reference  in the S-4  Registration  Statement  or the  Proxy
Statement and  Prospectus (as such terms are defined in Section 7.5 hereof) will
(i) in the  case of the  S-4  Registration  Statement,  at the  time it  becomes
effective and at the Effective Time,  contain any untrue statement of a material
fact or omit to state  any  material  fact  required  to be  stated  therein  or
necessary in order to make the statements therein not misleading, or (ii) in the
case of the Proxy  Statement and  Prospectus,  at the time of the mailing of the
Proxy  Statement  and  Prospectus  and  at  the  time  of  the  meeting  of  the
shareholders of PSP11,  contain any untrue  statement of a material fact or omit
to state any material fact  required to be stated  therein or necessary in order
to make the statements  therein,  in light of the circumstances under which they
are made, not misleading.

         4.10 Insurance.  All material  insurance of PSP11 is currently in full
force and effect and PSP11 has reported all claims and occurrences to the extent
required by such insurance.

         4.11 PSP11  Exchange  Properties.  PSP11 has valid and  insurable  fee
simple title to the PSP11 Exchange  Properties,  free and clear of all liens and
encumbrances,  subject to certain matters that do not materially  impair the use
or value of the respective PSP11 Exchange Property to which they relate.

         4.12 PSI Exchange Properties.  PSP11 agrees that it will not dispose of
the PSI  Exchange  Properties  for at  least a period  of two  years  after  the
Effective Time.

         4.13 Disclosure.  The  representations  and warranties by PSP11 in this
Agreement and any certificate or document delivered by it pursuant hereto do not
and will not contain any untrue  statement of a material fact or omit to state a
material fact necessary to make the statements  contained  herein or therein not
misleading.




     5.  Representations,   Warranties  and  Agreements  of  AOPP.  AOPP  hereby
represents, warrants and agrees with PSP11 and PSI that:

         5.1  Authorization.  Subject  to  approval  of  this  Agreement  by the
shareholders  of AOPP,  (i) the  execution,  delivery  and  performance  of this
Agreement  by AOPP  has been  duly  authorized  and  approved  by all  necessary
corporate  action of AOPP and (ii) AOPP has all  necessary  corporate  power and
authority to enter into this Agreement, to perform its obligations hereunder and
to complete the transactions contemplated hereby.

         5.2  Organization  and  Related  Matters.  AOPP is a  corporation  duly
organized,  existing  and in  good  standing  under  the  laws of the  State  of
California,  with all requisite  corporate power and authority to own, lease and
operate  its  properties  and to carry on its  business  as and where now owned,
leased,  operated or carried on, as the case may be; and is duly qualified to do
business as a foreign  corporation and is in good standing in each  jurisdiction
in which the  property  owned,  leased or  operated  by it or the  nature of the
business carried on by it requires such  qualification  and where the failure to
so qualify would have a material  adverse  effect on the  business,  properties,
results of operations or financial condition of AOPP.

         5.3  Capital Stock.  The  authorized  capital  stock  of  AOPP consists
solely of (i) 100,000,000 shares of Common Stock ($.10 par value),  3,523,500 of
which were issued and  outstanding  as of August 18,  1997 and (ii)  100,000,000
shares of  Preferred  Stock  ($.10 par  value),  none of which  were  issued and
outstanding as of August 18, 1997. All of the issued and  outstanding  shares of
Common Stock of AOPP have been duly and validly  authorized and issued,  and are
fully paid and nonassessable.

         5.4  Consents and  Approvals; No  Violation.  Neither the execution and
delivery of this  Agreement  nor the  consummation  by AOPP of the  transactions
contemplated  hereby  will:  (i)  conflict  with or result in any  breach of any
provision of its Articles of Incorporation or Bylaws;  (ii) require any consent,
waiver, approval, authorization or permit of, or filing with or notification to,
any  governmental  or regulatory  authority,  except (A) in connection  with the
applicable requirements,  if any, of the HSR Act, (B) pursuant to the applicable
requirements  of the  federal  securities  laws and the  rules  and  regulations
promulgated  thereunder,  (C) the filing of the Merger  Agreement  and Officers'
Certificates  pursuant to the GCLC and  appropriate  documents with the relevant
authorities  of other states in which AOPP is authorized to do business,  (D) in
connection  with any state or local tax which is  attributable to the beneficial
ownership  of AOPP's real  property,  (E) as may be  required by any  applicable
state  securities  or  takeover  laws,  or (F) where the  failure to obtain such
consent,  approval,   authorization  or  permit,  or  to  make  such  filing  or
notification,  would not in the aggregate have a material adverse effect on AOPP
or  adversely  affect  the  ability  of  AOPP  to  consummate  the  transactions
contemplated  hereby;  (iii) result in a violation or breach of, or constitute a
default (or give rise to any right of termination, cancellation or acceleration)
under any of the terms, conditions or provisions of any note, license, mortgage,
agreement or other  instrument  or obligation to which AOPP is a party or any of
its properties or assets may be bound, except for such violations,  breaches and
defaults  which, in the aggregate,  would not have a material  adverse effect on



AOPP or  adversely  affect the ability of AOPP to  consummate  the  transactions
contemplated hereby; or (iv) assuming the consents, approvals, authorizations or
permits and filings or  notifications  referred to in this  Section 5.4 are duly
and timely  obtained  or made,  violate  any order,  writ,  injunction,  decree,
statute,  rule or  regulation  applicable  to AOPP or its  properties or assets,
except for violations  which would not in the aggregate have a material  adverse
effect  on AOPP or  adversely  affect  the  ability  of AOPP to  consummate  the
transactions contemplated hereby.

         5.5  Litigation.  There is no  litigation,  proceeding or  governmental
investigation which, individually or in the aggregate, is or may be material and
adverse,  pending  or, to the  knowledge  of AOPP,  threatened  against  AOPP or
involving any of its properties or assets.

         5.6  Financial Statements.  The financial  statements of AOPP as of and
for the periods  ended  December 31,  1994,  1995 and 1996 and June 30, 1996 and
1997,  have been  prepared in  accordance  with  generally  accepted  accounting
principles applied on a basis consistent with prior periods (except as otherwise
noted  therein),  and present fairly the financial  position of AOPP as of their
respective  dates,  and  the  results  of  operations  of AOPP  for the  periods
presented  therein  (subject,  in the case of the  unaudited  interim  financial
statements, to normal year-end adjustments).

         5.7  Absence of Certain  Changes or Events.  Since January 1, 1997, the
business of AOPP has been  carried on only in the  ordinary and usual course and
there has not been any  material  adverse  change in its  business,  results  of
operations or financial condition, or any damage or destruction in the nature of
a casualty loss,  whether covered by insurance or not, that would materially and
adversely affect its properties, business or results of operations.

         5.8  S-4 Registration Statement and  Proxy  Statement  and  Prospectus.
None of the information supplied or to be supplied  by  AOPP  for  inclusion  or
incorporation  by  reference  in the S-4  Registration  Statement  or the  Proxy
Statement and Prospectus (as those terms are defined in Section 7.5 hereof) will
(i) in the  case of the  S-4  Registration  Statement,  at the  time it  becomes
effective and at the Effective Time,  contain any untrue statement of a material
fact or omit to state  any  material  fact  required  to be  stated  therein  or
necessary in order to make the statements therein not misleading, or (ii) in the
case of the Proxy  Statement and  Prospectus,  at the time of the mailing of the
Proxy  Statement  and  Prospectus  and  at  the  time  of  the  meeting  of  the
shareholders of PSP11,  contain any untrue  statement of a material fact or omit
to state any material fact  required to be stated  therein or necessary in order
to make the statements  therein,  in light of the circumstances under which they
are made, not misleading.

         5.9  Insurance.  All  material  insurance  of AOPP is currently in full
force and effect and AOPP has reported all claims and  occurrences to the extent
required by such insurance.

         5.10 Disclosure.  The  representations  and warranties by AOPP in this
Agreement and any certificate or document delivered by it pursuant hereto do not
and will not contain any untrue  statement of a material fact or omit to state a
material fact necessary to make the statements  contained  herein or therein not
misleading.

     6.  Representations,   Warranties   and  Agreements  of  PSI.  PSI  hereby
represents, warrants and agrees with PSP11 and AOPP that:


         6.1  Authorization.  The  execution,  delivery and  performance of this
Agreement  by PSI  has  been  duly  authorized  and  approved  by all  necessary
corporate action of PSI, and PSI has all necessary corporate power and authority
to enter  into this  Agreement,  to perform  its  obligations  hereunder  and to
complete the transactions contemplated hereby.

         6.2  Organization  and  Related  Matters.  PSI  is a  corporation  duly
organized,  existing  and in  good  standing  under  the  laws of the  State  of
California,  with all requisite  corporate power and authority to own, lease and
operate  its  properties  and to carry on its  business  as and where now owned,
leased,  operated or carried on, as the case may be; and is duly qualified to do
business as a foreign  corporation and is in good standing in each  jurisdiction
in which the  property  owned,  leased or  operated  by it or the  nature of the
business carried on by it requires such  qualification  and where the failure to
so qualify would have a material  adverse  effect on the  business,  properties,
results of operations or financial condition of PSI.

         6.3  S-4 Registration Statement and Proxy  Statement  and  Prospectus.
None of the information supplied or to be supplied  by  PSI  for  inclusion  or
incorporation  by  reference  in the S-4  Registration  Statement  or the  Proxy
Statement and Prospectus (as those terms are defined in Section 7.5 hereof) will
(i) in the  case of the  S-4  Registration  Statement,  at the  time it  becomes
effective and at the Effective Time,  contain any untrue statement of a material
fact or omit to state  any  material  fact  required  to be  stated  therein  or
necessary in order to make the statements therein not misleading, or (ii) in the
case of the Proxy  Statement and  Prospectus,  at the time of the mailing of the
Proxy  Statement  and  Prospectus  and  at  the  time  of  the  meeting  of  the
shareholders of PSP11,  contain any untrue  statement of a material fact or omit
to state any material fact  required to be stated  therein or necessary in order
to make the statements  therein,  in light of the circumstances under which they
are made, not misleading.

         6.4  PSI Exchange Properties.  PSI has valid and  insurable  fee simple
title  to  the  PSI  Exchange  Properties,  free  and  clear  of all  liens  and
encumbrances,  subject to certain matters that do not materially  impair the use
or value of the respective PSI Exchange Property to which they relate.

         6.5  PSP11 Exchange Properties.  PSI agrees that it will not dispose of
the PSP11  Exchange  Properties  for at least a period  of two  years  after the
Effective Time.

     7.  Covenants and Agreements.

         7.1  Ordinary Course. Except as contemplated by this Agreement,  during
the period from the date of this Agreement to the Effective  Time, each of PSP11
and AOPP will carry on its business in the ordinary course in substantially  the
same  manner as  heretofore  conducted  and use all  reasonable  efforts to: (a)
preserve intact its present  business,  organization and goodwill,  (b) maintain
all permits,  licenses and  authorizations  required by applicable  laws and (c)
keep  available  the  services  of  its  present   employees  and  preserve  its
relationships with customers, suppliers, lenders, lessors, governmental entities



and others having  business or regulatory  dealings with it. Without the consent
of the other, PSP11 and AOPP will not issue any capital stock or debt securities
convertible into capital stock.  Each of PSP11 and AOPP will promptly notify the
other of any  event or  occurrence  not in the  ordinary  and  usual  course  of
business  or which  may have a  material  adverse  effect on the  properties  or
financial condition of such party.

         7.2  Meeting of Shareholders.

              7.2.1     PSP11.PSP11 will take all action necessary in accordance
with  applicable  law to convene a meeting of its  shareholders  as  promptly as
practicable  to  consider  and vote upon  approval of this  Agreement,  it being
understood that (i) the principal terms of the Agreement must be approved by the
affirmative vote of a majority of the outstanding  shares of Common Stock Series
A, Common Stock Series B and Common Stock Series C of PSP11, counted together as
a single  class,  and (ii) the shares of Common  Stock Series B and Common Stock
Series  C of  PSP11  will  be  voted  with  the  holders  of a  majority  of the
unaffiliated shares of Common Stock Series A of PSP11.

              7.2.2     AOPP. AOPP will take all action necessary in accordance
with applicable law to convene a meeting of its  shareholders  as  promptly  as
practicable to consider and vote upon approval of this Agreement.

         7.3  Tax  Reporting. Each of PSP11 and AOPP agrees to report the Merger
for federal  and state  income tax  purposes,  as a  reorganization  of the type
described in Section 368(a)(1)(A) of the Code.

         7.4  Acquisition  Proposals.   PSP11  will  not  initiate,  solicit  or
encourage,  directly or indirectly,  any inquiries or the making of any proposal
with respect to a merger,  consolidation,  share exchange or similar transaction
involving PSP11, or any purchase of all or any significant portion of the assets
of  PSP11,  or any  equity  interest  in  PSP11,  other  than  the  transactions
contemplated hereby (an "Acquisition  Proposal"),  or engage in any negotiations
concerning,  or provide  any  confidential  information  or data to, or have any
discussions  with,  any person  relating to an Acquisition  Proposal;  provided,
however,  that the Board of Directors on behalf of PSP11 may furnish or cause to
be  furnished   information  and  may   participate  in  such   discussions  and
negotiations  through its representatives  with persons who have sought the same
if the failure to provide such  information or participate in such  negotiations
and  discussions  might  cause the members of the Board of  Directors  to breach
their fiduciary duty to PSP11's  shareholders under applicable law as advised by
counsel.  PSP11 will notify PSI  immediately  if any such inquiries or proposals
are  received  by,  any  such   information  is  requested  from,  or  any  such
negotiations  or discussions are sought to be initiated or continued with PSP11,
and will keep AOPP  informed of the status and terms of any such  proposals  and
any such negotiations or discussions.

         7.5  Registration  and Proxy  Statements.  PSP11 and AOPP will promptly
prepare and file with the SEC a preliminary  proxy  statement in connection with
the vote of  shareholders  of PSP11 with respect to the Merger.  PSP11 will,  as
promptly as practicable,  prepare and file with the SEC a registration statement
on  Form  S-4  (the   "S-4   Registration   Statement"),   containing   a  proxy
statement/prospectus,  in connection with the registration  under the Securities
Act of 1933, as amended (the "Securities  Act") of the PSP11 Shares to be issued
to  holders  of AOPP  Shares in the  Merger  (such  proxy  statement/prospectus,



together with any  amendments  thereof or  supplements  thereto,  in the form or
forms to be mailed or delivered  to the  shareholders  of PSP11 and AOPP,  being
herein called the "Proxy  Statement and  Prospectus").  PSP11 and AOPP will each
use its best  efforts  to have or cause  the S-4  Registration  Statement  to be
declared  effective  as  promptly as  practicable,  and also will take any other
action  required to be taken under federal or state  securities  laws, and PSP11
and AOPP will use their best efforts to cause the Proxy Statement and Prospectus
to be mailed to their respective  shareholders at the earliest practicable date.
PSP11  agrees  that if at any time  prior to the  Effective  Time any event with
respect to PSP11  should occur which is required to be described in an amendment
of,  or a  supplement  to,  the  Proxy  Statement  and  Prospectus  or  the  S-4
Registration Statement,  such event shall be so described, and such amendment or
supplement  shall  be  promptly  filed  with the SEC and,  as  required  by law,
disseminated to the  shareholders of PSP11 and AOPP and (ii) the Proxy Statement
and  Prospectus  will (with  respect to PSP11) comply as to form in all material
respects with the requirements of the federal  securities laws. AOPP agrees that
(i) if at any time prior to the  Effective  Time any event with  respect to AOPP
should  occur  which is  required  to be  described  in an  amendment  of,  or a
supplement  to,  the Proxy  Statement  and  Prospectus  or the S-4  Registration
Statement,  such event shall be so described,  and such  amendment or supplement
shall be promptly  filed with the SEC and, as required by law,  disseminated  to
the shareholders of PSP11 and (ii) the Proxy Statement and Prospectus will (with
respect  to  AOPP)  comply  as  to  form  in  all  material  respects  with  the
requirements of the federal securities laws.

         7.6  Best Efforts.  Each of PSP11 and AOPP shall:  i) promptly make its
respective filings and thereafter make any other required  submissions under all
applicable  laws  with  respect  to  the  Merger  and  the  other   transactions
contemplated hereby; and (ii) use its best efforts to promptly take, or cause to
be  taken,  all other  actions  and do,  or cause to be done,  all other  things
necessary,   proper  or   appropriate  to  consummate  and  make  effective  the
transactions contemplated by this Agreement as soon as practicable.

         7.7  Registration and Listing of PSP11 Shares.  PSP11 will use its best
efforts to register  under the  applicable  provisions of the Securities Act the
shares of PSP11 Common Stock to be issued in the Merger and to cause such shares
to be listed for trading on the AMEX upon official notice of issuance.

         7.8  Distributions.  Neither  PSP11 nor AOPP will, at any time prior to
the Effective Time, declare or pay any cash distribution on its capital stock or
make any  other  distribution  of  assets to its  shareholders,  except  regular
quarterly dividends consistent with prior practice.

     8.  Conditions.

         8.1  Conditions to Each Party's Obligations. The respective obligations
of each party to consummate the transactions  contemplated by this Agreement are
subject to the  fulfillment  at or prior to the Closing of each of the following
conditions, any or all of which may be waived in whole or in part, to the extent
permitted by applicable law:


              8.1.1     Shareholder   Approval.  This  Agreement  and  the 
transactions contemplated  hereby shall have been duly approved by both the
shareholders of PSP11 and the shareholders of AOPP as contemplated by Sections 
7.2.1 and 7.2.2 hereof.

              8.1.2     Governmental  and  Regulatory  Consents.  All filings 
required to be made  prior to the  Effective  Time  with,  and all  consents,
approvals, permits  and  authorizations  required to be  obtained prior to the 
Effective Time from, governmental and regulatory  authorities in connection with
the execution and delivery of this  Agreement  and  the  consummation  of the  
transactions contemplated hereby (including the expiration of the waiting period
requirements of the HSR Act) shall have been made or obtained (as the case may 
be) without material restrictions, except where the failure to obtain  such
consents, approvals, permits and authorizations could not reasonably be expected
to have a material adverse effect on PSP11, AOPP or PSI.

              8.1.3     Litigation.  No court or governmental or regulatory 
authority of competent  jurisdiction  shall have enacted,  issued,  promulgated,
enforced or entered any statute, rule, regulation,  judgment, decree, injunction
or other order (whether temporary, preliminary or permanent) or taken any action
which  prohibits  the  consummation  of the  transactions  contemplated  by this
Agreement;  provided,  however, that the party invoking this condition shall use
its best efforts to have any such  judgment,  decree,  injunction or other order
vacated.

              8.1.4     Registration Statement. The S-4 Registration Statement 
shall have been declared  effective and no stop order  suspending  effectiveness
shall have been issued, no action, suit,  proceeding or investigation by the SEC
to  suspend  the  effectiveness   thereof  shall  have  been  initiated  and  be
continuing,  and all necessary approvals under federal and state securities laws
relating to the  issuance or trading of the shares of PSP11  Common  Stock to be
issued in the Merger shall have been received.

              8.1.5     Listing of PSP11 Shares on AMEX.  The shares of PSP11 
Common Stock to be issued in the Merger shall have been  approved for listing on
the AMEX upon official notice of issuance.

              8.1.6     PSP11  Fairness  Opinion.  The Board of  Directors  of 
PSP11 shall have  received the opinion of Jefferies & Company,  Inc. in form and
substance  satisfactory  to it to the effect  that the terms of the Merger  are,
from a financial  point of view, fair to the public  shareholders of PSP11,  and
such opinion shall not have been withdrawn or revoked.

              8.1.7     Tax Opinion.  The Board of Directors of PSP11 and AOPP 
shall have  received a legal opinion of Hogan & Hartson  L.L.P.  that the Merger
will qualify as a tax-free reorganization under Section 368(a) of the Code.

              8.1.8     PSI Board  Approval. This Agreement and the transactions
contemplated  hereby shall have been duly  approved by the Board of Directors of
PSI.

              8.1.9     Merger and Exchange. The Merger and the  Exchange  are
conditioned on each other.


         8.2  Conditions to Obligations  of PSP11.  The  obligations of PSP11 to
consummate the  transactions  contemplated  by this Agreement are subject to the
fulfillment at or prior to the Closing of the following conditions, which may be
waived in whole or in part by PSP11 to the extent permitted by applicable law:

              8.2.1     Accuracy of Representations; Performance of Agreements. 
Each of the  representations  and  warranties  of AOPP and PSI contained in this
Agreement  shall be true and correct in all  material  respects at and as of the
Closing Date as if made at and as of the Closing Date (except to the extent they
relate to a particular  date) and AOPP and PSI shall have  performed or complied
with all agreements and covenants  required by this Agreement to be performed or
complied with by them at or prior to the Closing.

              8.2.2     Deeds  and  Cash.  PSI shall have delivered into escrow
deeds,  in form  and  substance  satisfactory  to  PSP11,  for the PSI  Exchange
Properties.

              8.2.3     Certificate of Officers. PSP11 shall have received  such
certificates  of  officers  of AOPP and PSI as PSP11 may  reasonably  request in
connection with the Closing,  including upon request a certificate  satisfactory
to it of the Chief Executive  Officers and the Chief Financial  Officers of AOPP
and PSI to the effect that, to the best of their knowledge,  all representations
and warranties of their respective  corporation  contained in this Agreement are
true and correct in all  material  respects at and as of the Closing  Date as if
made  at and as of the  Closing  Date,  and  their  respective  corporation  has
performed  or  complied  with all  agreements  and  covenants  required  by this
Agreement to be performed or complied with at or prior to the Closing.

              8.2.4     Title to Properties; Environmental Audits. PSP11 in its 
sole  discretion  shall be satisfied as to the status of title to (including the
existence  and  effect  of  liens  and  encumbrances),  and  the  results  of an
environmental  audit of, each of the real  properties  owned by AOPP and each of
the PSI Exchange Properties.

              8.2.5     Dissenting Shares.  None of the AOPP Shares shall  have 
become Dissenting Shares.

         8.3  Conditions to  Obligations  of AOPP.  The  obligations  of AOPP to
consummate the  transactions  contemplated  by this Agreement are subject to the
fulfillment at or prior to the Closing of the following conditions, which may be
waived in whole or in part by AOPP to the extent permitted by applicable law.

              8.3.1     Accuracy of Representations; Performance of Agreements.
Each of the  representations  and  warranties of PSP11 and PSI contained in this
Agreement  shall be true and correct in all  material  respects at and as of the
Closing Date as if made at and as of the Closing Date (except to the extent they
relate to a particular  date) and PSP11 and PSI shall have performed or complied
in all material  respects with all  agreements  and  covenants  required by this
Agreement to be performed or complied with by them at or prior to the Closing.

              8.3.2     Certificate of Officers. AOPP shall have  received  such
certificates  of  officers  of PSP11 and PSI as AOPP may  reasonably  request in
connection with the Closing,  including upon request a certificate  satisfactory


to it of the Chief Executive  Officers and the Chief Financial Officers of PSP11
and PSI to the effect that, to the best of their knowledge,  all representations
and warranties of their respective  corporation  contained in this Agreement are
true and correct in all  material  respects at and as of the Closing  Date as if
made  at and as of the  Closing  Date,  and  their  respective  corporation  has
performed  or  complied  with all  agreements  and  covenants  required  by this
Agreement to be performed or complied with at or prior to the Closing.

              8.3.3     Title to Properties; Environmental Audits.  AOPP in its
sole  discretion  shall be satisfied as to the status of title to (including the
existence  and  effect  of  liens  and  encumbrances),  and  the  results  of an
environmental audit of, each of the real properties owned by PSP11.

              8.3.4     Dissenting Shares. Less than 5% of the outstanding PSP11
Shares shall have become Dissenting Shares.

         8.4  Conditions  to  Obligations  of  PSI.  The  obligations  of PSI to
consummate the  transactions  contemplated  by this Agreement are subject to the
fulfillment at or prior to the Closing of the following conditions, which may be
waived in whole or in part by PSI to the extent permitted by applicable law.

              8.4.1     Accuracy of Representations; Performance of Agreements.
Each of the  representations  and warranties of PSP11 and AOPP contained in this
Agreement  shall be true and correct in all  material  respects at and as of the
Closing Date as if made at and as of the Closing Date (except to the extent they
relate to a particular date) and PSP11 and AOPP shall have performed or complied
in all material  respects with all  agreements  and  covenants  required by this
Agreement to be performed or complied with by them at or prior to the Closing.

              8.4.2     Deeds.  PSP11 shall have delivered into escrow deeds, 
in form and satisfactory to PSI, for the PSP11 Exchange Properties.

              8.4.3     Certificate of Officers.  PSI shall have  received  such
certificates  of  officers  of PSP11 and AOPP as PSI may  reasonably  request in
connection with the Closing,  including upon request a certificate  satisfactory
to it of the Chief Executive  Officers and the Chief Financial Officers of PSP11
and AOPP to the effect that, to the best of their knowledge, all representations
and warranties of their respective  corporation  contained in this Agreement are
true and correct in all  material  respects at and as of the Closing  Date as if
made  at and as of the  Closing  Date,  and  their  respective  corporation  has
performed  or  complied  with all  agreements  and  covenants  required  by this
Agreement to be performed or complied with at or prior to the Closing.

     9.  Termination.

         9.1  Termination  by  Mutual Consent. This Agreement may be terminated 
and the Merger may be abandoned at any time prior to the Effective Time,  before
or after shareholder  approval, by the mutual written consent of PSP11, AOPP and
PSI.

         9.2  Termination  by  PSP11,  AOPP  or  PSI.  This  Agreement  may be
terminated  and the Merger and the  Exchange  may be  abandoned by action of the
Board of Directors  of any of PSP11,  AOPP or PSI if (i) both the Merger and the
Exchange shall not have been consummated by December 31, 1998 (provided that the
right to  terminate  this  Agreement  under  this  Section  9.2(i)  shall not be
available  to any party  whose  failure to  fulfill  any  obligation  under this
Agreement  has been the cause of or  resulted  in the  failure  of the Merger to
occur on or before such date);  (ii) any court of competent  jurisdiction in the
United States or some other governmental body or regulatory authority shall have
issued an  order,  decree  or  ruling  or taken  any  other  action  permanently
restraining,  enjoining  or  otherwise  prohibiting  the Merger and such  order,
decree,  ruling or other action shall have become  final and  nonappealable;  or
(iii) the shareholders of either PSP11 or AOPP shall have failed to approve this
Agreement and the transactions  contemplated hereby at its respective meeting of
shareholders.

         9.3  Termination by PSP11. This Agreement may be terminated  by  PSP11
and the  Merger  and the  Exchange  may be  abandoned  at any time  prior to the
Effective  Time,  if (i) AOPP or PSI shall have failed to comply in any material
respect with any of the  covenants,  conditions or agreements  contained in this
Agreement to be complied with or performed by AOPP or PSI,  respectively,  at or
prior to such date of  termination,  which  failure to comply has not been cured
within five  business  days  following  notice to such party of such  failure to
comply or (ii) any  representation  or warranty of AOPP or PSI contained in this
Agreement shall not be true in all material respects when made, which inaccuracy
or breach (if  capable of cure) has not been cured  within  five  business  days
following notice to such party of the inaccuracy or breach,  or on and as of the
Closing as if made on and as of the Closing Date.

         9.4  Termination by AOPP.  This Agreement may be terminated by AOPP and
the Merger and the Exchange may be abandoned at any time prior to the  Effective
Time,  before or after  shareholder  approval,  if (i)  PSP11 or PSI shall  have
failed to comply in any material  respect with any of the covenants,  conditions
or  agreements  contained in this  Agreement to be complied with or performed by
PSP11  or PSI,  respectively,  at or prior to such  date of  termination,  which
failure to comply has not been cured within five business days following  notice
to such party of such failure to comply or (ii) any  representation  or warranty
of PSP11 or PSI  contained in this  Agreement  shall not be true in all material
respects when made,  which inaccuracy or beach (if capable of cure) has not been
cured within five business days following notice to such party of the inaccuracy
or breach, or on and as of the Closing as if made on and as of the Closing Date.

         9.5  Termination by PSI. This Agreement may be terminated by  PSI  and
the Merger and the Exchange may be abandoned at any time prior to the  Effective
Time,  before or after  shareholder  approval,  if (i) PSP11 or AOPP  shall have
failed to comply in any material  respect with any of the covenants,  conditions
or  agreements  contained in this  Agreement to be complied with or performed by
PSP11 or AOPP,  respectively,  at or prior to such  date of  termination,  which
failure to comply has not been cured within five business days following  notice
to such party of such failure to comply or (ii) any  representation  or warranty
of PSP11 or AOPP contained in this  Agreement  shall not be true in all material
respects when made,  which inaccuracy or beach (if capable of cure) has not been
cured within five business days following notice to such party of the inaccuracy
or breach, or on and as of the Closing as if made on and as of the Closing Date.

         9.6  Effect of Termination and Abandonment. In the event of termination
of this  Agreement and  abandonment  of the Merger and the Exchange  pursuant to
this  Section  9, no party (or any  directors,  officers,  employees,  agents or
representatives  of any party) shall have any liability or further obligation to
any other  party or any person who  controls a party  within the  meaning of the
Securities  Act,  except as  provided in Section  10.1 and except  that  nothing
herein will relieve any party from liability for any breach of this Agreement.

     10. Miscellaneous.

         10.1 Payment of Expenses.  If the Merger and Exchange are  consummated,
the Surviving  Corporation shall pay all the expenses incident to preparing for,
entering  into and  carrying  out this  Agreement  and the  consummation  of the
transactions   contemplated   hereby.   If  the  Merger  and  Exchange  are  not
consummated, each of PSP11, AOPP and PSI shall pay its own expenses, except that
PSP11,  AOPP and PSI  shall  each pay  one-third  of any  expenses  incurred  in
connection  with the printing of the S-4  Registration  Statement  and the Proxy
Statement and Prospectus, the real estate appraisals and environmental audits of
the properties of PSP11,  AOPP and PSI and preparation for real estate closings,
and any filing fees under the HSR Act,  the  Securities  Act and the  Securities
Exchange Act of 1934, as amended.

         10.2 Survival  of  Representations,   Warranties  and  Covenants.  The
respective  representations  and  warranties  of PSP11,  AOPP and PSI  contained
herein or in any certificate or document  delivered pursuant hereto shall expire
with and be terminated and  extinguished by the  effectiveness of the Merger and
shall not survive the Effective  Time.  The sole right and remedy arising from a
misrepresentation  or  breach of  warranty,  or from the  failure  of any of the
conditions to be met,  shall be the  termination  of this Agreement by the other
party.  This  Section  10.2 shall not limit any  covenant  or  agreement  of the
parties,  which by its terms contemplates  performance at or after the Effective
Time.

         10.3 Modification  or Amendment.  The parties may modify or amend this
Agreement  by  written  agreement  authorized  by the  Boards of  Directors  and
executed and delivered by officers of the respective parties; provided, however,
that after approval of this Agreement by the  shareholders  of PSP11 or AOPP, no
amendment  shall be made which changes any of the principal  terms of the Merger
or this Agreement, without the approval of the shareholders of such corporation.

         10.4 Waiver of  Conditions.  The  conditions  to each of the  parties'
obligations  to consummate the Merger are for the sole benefit of such party and
may be  waived  by such  party in whole or in part to the  extent  permitted  by
applicable law.

         10.5 Governing  Law. This Agreement  shall be governed by and construed
in accordance with the laws of the State of California, without giving effect to
the principles of conflict of laws thereof.



         10.6 Interpretation.  This Agreement has been negotiated by the parties
and is to be  interpreted  according  to its fair  meaning as if the parties had
prepared  it together  and not  strictly  for or against any party.  Each of the
capitalized  terms  defined in this  Agreement  shall,  for all purposes of this
Agreement (and whether  defined in the plural and used in the singular,  or vice
versa),  have the  respective  meaning  assigned  to such term in the Section in
which such meaning is set forth.  References in this Agreement to "parties" or a
"party" refer to parties to this Agreement unless expressly indicated otherwise.
At each place in this  Agreement  where the context so requires,  the masculine,
feminine or neuter gender  includes the others and the singular or plural number
includes the other. "Including" means "including without limitation."

         10.7 Headings.  The descriptive  headings contained in the Sections and
subsections  of this  Agreement are for  convenience of reference only and shall
not affect in any way the meaning or interpretation of this Agreement.

         10.8 Parties in Interest. This Agreement, and the rights, interests and
obligations  created by this  Agreement,  shall bind and inure to the benefit of
the parties and their  respective  successors and permitted  assigns,  and shall
confer  no  right,  benefit  or  interest  upon  any  other  person,   including
shareholders of the respective parties.

         10.9 Notices. All notices or other communications required or permitted
under this  Agreement  shall be in writing and shall be delivered  personally or
sent by U.S. mail,  postage prepaid,  addressed as follows or such other address
as the party to be  notified  has  furnished  in  writing  by a notice  given in
accordance with this Section 10.9:

                             If to PSP11:

                             Public Storage Properties XI, Inc.
                             701 Western Avenue, Suite 200
                             Glendale, California 91201-2397
                             Attention: B. Wayne Hughes
                               Chief Executive Officer

                             If to AOPP:

                             American Office Park Properties, Inc.
                             701 Western Avenue, Suite 200
                             Glendale, California 91201-2397
                             Attention: Ronald L. Havner, Jr.
                               Chief Executive Officer

                             If to PSI:

                             Public Storage, Inc.
                             701 Western Avenue, Suite 200
                             Glendale, California 91201-2397
                             Attention: Harvey Lenkin
                               President



Any  such  notice  or  communication  shall  be  deemed  given as of the date of
delivery, if delivered  personally,  or on the second day after deposit with the
U.S. Postal Service, if sent by U.S. mail.

         10.10 Counterparts.  This  Agreement  may be  executed  in two or more
counterparts,  each of which shall be deemed to be an original, but all of which
shall be considered one and the same agreement.

         10.11 Assignment.  No rights,  interests or obligations of either party
under this  Agreement  may be assigned or  delegated  without the prior  written
consent of the other party.

         10.12 Entire Agreement. This Agreement, including the Merger Agreement,
embodies the entire agreement and understanding  between the parties  pertaining
to  the  subject   matter  hereof,   and   supersedes   all  prior   agreements,
understandings,  negotiations,  representations and discussions, whether written
or oral.

         10.13 Severable Provisions.  If any of the provisions of this Agreement
may be determined to be illegal or otherwise unenforceable, in whole or in part,
the remaining provisions, and any partially enforceable provisions to the extent
enforceable, shall nevertheless be binding and enforceable.

         10.14 Further  Action.  If at any time after the Effective  Time,  the
Surviving Corporation shall determine that any assignments,  transfers, deeds or
other  assurances  are  necessary or desirable to vest,  perfect or confirm,  of
record or  otherwise,  in the  Surviving  Corporation,  title to any property or
rights  of AOPP,  the  officers  of  either  Constituent  Corporation  are fully
authorized  in the  name  of AOPP or  otherwise  to  execute  and  deliver  such
documents  and do all things  necessary  and proper to vest,  perfect or confirm
title to such property or rights in the Surviving Corporation.

     IN WITNESS WHEREOF,  the parties have entered into this Agreement as of the
date first above written.

                                        PUBLIC STORAGE PROPERTIES XI, INC.

                                        By:   /s/ B. WAYNE HUGHES
                                              -----------------------------
                                              B. Wayne Hughes
                                              Chief Executive Officer

                                        AMERICAN OFFICE PARK PROPERTIES, INC.

                                        By:   /s/ RONALD L. HAVNER, JR.
                                              -----------------------------
                                              Ronald L. Havner, Jr.
                                              Chief Executive Officer

                                        PUBLIC STORAGE, INC.

                                        By:   /s/ HARVEY LENKIN
                                              -----------------------------
                                              Harvey Lenkin
                                              President


                                                                      Exhibit A
                                                                      ---------
                               AGREEMENT OF MERGER

     THIS AGREEMENT OF MERGER  ("Agreement") is entered into as of this ____ day
of  __________,  1997,  by and between  PUBLIC  STORAGE  PROPERTIES  XI, INC., a
California  corporation  ("PSP11") and AMERICAN OFFICE PARK PROPERTIES,  INC., a
California corporation ("AOPP") with reference to the following:

     A. PSP11 was incorporated in 1990 under the laws of California,  and on the
date hereof has  outstanding  _______________  shares of Common  Stock Series A,
$.01 par value (the "PSP11  Shares"),__________  shares of Common Stock Series B
and __________ shares of Common Stock Series C.

     B. AOPP was  incorporated in 1987 under the laws of California,  and on the
date hereof its  authorized  capital  stock  consists of  100,000,000  shares of
Common  Stock,  $.10 par value (the  "AOPP  Shares"),  ___________  of which are
issued and  outstanding  and  100,000,000  shares of  Preferred  Stock ($.10 par
value), none of which are issued and outstanding.

     C. PSP11,  AOPP and Public  Storage,  Inc.  ("PSI")  have  entered  into an
Agreement and Plan of Reorganization  dated as of August ___, 1997 (the "Plan"),
setting forth certain  representations,  warranties,  conditions  and agreements
pertaining to the Merger (as defined below).

     D. The Boards of  Directors of PSP11,  AOPP and PSI have  approved the Plan
and this Agreement of Merger,  and the requisite  shareholder  approval has been
obtained.

     NOW, THEREFORE, the parties agree as follows:

                                    ARTICLE I

          1.1 The Merger. At the Effective Time (as defined below), AOPP will be
merged  with and into  PSP11 (the  "Merger")  and PSP11  shall be the  surviving
corporation. PSP11 and AOPP are sometimes collectively referred to herein as the
"Constituent  Corporations"  and  PSP11,  as the  surviving  corporation  of the
Merger, is sometimes referred to herein as the "Surviving Corporation."

          1.2 Effective  Time. The Merger shall become  effective at the time at
which this  Agreement,  together with the requisite  Officers'  Certificates  of
PSP11 and AOPP, are filed with the California Secretary of State (the "Effective
Time").

          1.3 Effect of the Merger. At the Effective Time:

              (a) The separate  corporate  existence of AOPP shall cease and the
Surviving  Corporation shall thereupon succeed,  without other transfer,  to all
the  rights  and  property  of AOPP and  shall be  subject  to all the debts and

                                      A-1


liabilities  of AOPP in the same  manner  as if the  Surviving  Corporation  had
itself incurred them; all rights of creditors and all liens upon the property of
each of the Constituent  Corporations  shall be preserved  unimpaired,  provided
that such liens upon property of AOPP shall be limited to the property  affected
thereby  immediately  prior to the Effective  Time; and any action or proceeding
pending by or against AOPP may be prosecuted  to judgment,  which shall bind the
Surviving Corporation,  or the Surviving Corporation may be proceeded against or
substituted in its place.

              (b) The  Articles  of  Incorporation  of PSP11,  as amended in the
following  respect at the Effective  Time,  shall continue to be the Articles of
Incorporation of the Surviving  Corporation until changed as provided by law and
its respective provisions. Article I shall be amended to read as follows:

              The name of this  corporation is American Office Park  Properties,
Inc.

              (c)  The  directors  of  the  Surviving  Corporation   immediately
following the Merger shall be the following:

               Ronald L. Havner, Jr.
               Harvey Lenkin
               Vern O. Curtis
               James Kropp
               Jack D. Steele
               Christopher Weil

                                   ARTICLE II

          2.1 Common Stock Series A of PSP11.  Each outstanding  share of Common
Stock Series A ($.01 par value) of PSP11 (the "PSP11  Shares") would continue to
be owned by holders of PSP11 Shares or converted  into the right to receive cash
as follows:

              (a) At the Effective  Time,  subject to Section 2.7.1 of the Plan,
each PSP11 Share as to which a cash  election has been made in  accordance  with
the provisions of Section 2.6 of the Plan and has not been revoked, relinquished
or lost pursuant to Section 2.6 of the Plan (the "Cash  Election  Shares") shall
be converted  into and shall  represent the right to receive  $20.50 in cash. As
soon as practicable  after the Effective  Time,  the registered  holders of Cash
Election  Shares shall be paid the cash to which they are entitled  hereunder in
respect of such Cash Election Shares.

              (b) At the  Effective  Time,  subject to Section 2.12 of the Plan,
each PSP11 Share (other than Cash Election Shares) shall continue to be owned by
the holders of the PSP11 Shares.

          2.2 Common Stock Series B and C of PSP11.  Each  outstanding  share of
Common Stock Series B and C ($.01 par value) of PSP11 (the "PSP11 Series B and C
Shares")  would be  converted  into the right to receive cash or PSP11 Shares as
follows:

                                      A-2


              (a) At the Effective  Time,  subject to Section 2.7.2 of the Plan,
each  PSP11  Series B and C Share as to which a cash  election  has been made in
accordance  with  the  provisions  of  Section  2.6 of the Plan and has not been
revoked, relinquished or lost pursuant to Section 2.6 of the Plan (the "Series B
and C Cash Election  Shares")  shall be converted  into and shall  represent the
right to receive  $17.71 in cash.  As soon as  practicable  after the  Effective
Time,  the  registered  holders of Series B and C Cash Election  Shares shall be
paid the cash to which they are  entitled  hereunder in respect of such Series B
and C Cash Election Shares.

              (b) At the  Effective  Time,  subject to Section 2.12 of the Plan,
each PSP11 Series B and C Share (other than Series B and C Cash Election Shares)
shall be converted into 0.8641 PSP11 Shares.

          2.3 AOPP  Shares.  Each  outstanding  share of Common  Stock ($.10 par
value) of AOPP (the "AOPP  Shares") would be converted into the right to receive
cash or PSP11 Shares as follows:

              (a) At the Effective  Time,  subject to Section 2.7.3 of the Plan,
each AOPP Share as to which a cash election has been made in accordance with the
provisions of Section 2.6 of the Plan and has not been revoked,  relinquished or
lost pursuant to Section 2.6 of the Plan (the "AOPP Cash Election Shares") shall
be converted  into and shall  represent the right to receive  $24.19 in cash. As
soon as practicable  after the Effective  Time,  the registered  holders of AOPP
Cash Election Shares shall be paid the cash to which they are entitled hereunder
in respect of such AOPP Cash Election Shares.

              (b) At the  Effective  Time,  subject to Section 2.12 of the Plan,
each AOPP Share (other than AOPP Cash Election  Shares) shall be converted  into
1.18 PSP11 Shares.

          2.4 Exchange of Certificates. After the Effective Time, each holder of
a certificate theretofore evidencing outstanding PSP11 Series B and C Shares and
AOPP  Shares  which were  converted  into PSP11  Shares  pursuant  hereto,  upon
surrender of such  certificate  to American  Stock Transfer & Trust Company (the
"Exchange  Agent") or such other  agent or agents as shall be  appointed  by the
Surviving Corporation,  shall be entitled to receive a certificate  representing
the number of whole PSP11  Shares into which the PSP11 Series B and C Shares and
AOPP Shares theretofore represented by the certificate so surrendered shall have
been converted and cash payment in lieu of fractional share  interests,  if any.
As soon as practicable  after the Effective Time, the Exchange Agent will send a
notice and a transmittal  form to each holder of PSP11 Series B and C Shares and
AOPP  Shares  of  record at the  Effective  Time  whose  stock  shall  have been
converted into PSP11 Shares,  advising such holder of the  effectiveness  of the
Merger and the procedure for  surrendering  to the Exchange  Agent  certificates
evidencing  PSP11  Series  B and C  Shares  and  AOPP  Shares  in  exchange  for
certificates evidencing PSP11 Shares.

          2.5 Status Until Surrendered. Until surrendered as provided in Section
2.6 hereof,  each outstanding  certificate  which,  prior to the Effective Time,
represented  PSP11 Series B and C Shares and AOPP Shares (other than  Dissenting


                                      A-3


Shares (as defined below), if any) will be deemed for all corporate  purposes to
evidence  ownership  of the number of whole  PSP11  Shares  into which the PSP11
Series B and C Shares and AOPP Shares evidenced thereby were converted. However,
until such  outstanding  certificates  formerly  evidencing PSP11 Series B and C
Shares and AOPP Shares are so  surrendered,  no  dividend  payable to holders of
record  of  PSP11  Shares  shall  be paid  to the  holders  of such  outstanding
certificates in respect of PSP11 Series B and C Shares and AOPP Shares, but upon
surrender  of such  certificates  by such  holders  there  shall be paid to such
holders the amount of any dividends  (without  interest)  theretofore  paid with
respect to such whole PSP11 Shares as of any record date on or subsequent to the
Effective  Time and the amount of any cash  (without  interest)  payable to such
holder in lieu of fractional share interests.

          2.6 Transfer of Shares.  After the Effective  Time,  there shall be no
further registration of transfers of PSP11 Series B and C Shares and AOPP Shares
on the corporate  records and, if certificates  formerly  evidencing such shares
are  presented  to the  Surviving  Corporation,  they  shall  be  cancelled  and
exchanged  for  certificates  evidencing  PSP11  Shares  and  cash  in  lieu  of
fractional share interests as herein provided.

          2.7 No Fractional Shares.  Notwithstanding any other term or provision
of this Agreement or the Plan, no fractional PSP11 Shares and no certificates or
script therefor,  or other evidence of ownership thereof,  will be issued in the
Merger.  In lieu of any such  fractional  share  interests,  each holder of AOPP
Shares or of PSP11 Series B and C Shares who would otherwise be entitled to such
fractional  share will,  upon  surrender of the  certificate  representing  such
shares,  receive a whole  PSP11  Share if such  fractional  share to which  such
holder would  otherwise  have been entitled is .5 of a PSP11 Share or more,  and
such  fractional  share shall be disregarded if it represents  less than .5 of a
PSP11  Share;  provided,  however,  that,  such  fractional  share  shall not be
disregarded if such  fractional  share to which such holder would otherwise have
been  entitled  represents  .5 of 1% or more of the total number of PSP11 Shares
such holder is entitled  to receive in the  Merger.  In such event,  such holder
shall be paid an amount in cash (without interest), rounded to the nearest $.01,
determined by multiplying  (i) the per share closing price on the American Stock
Exchange,  Inc. of the PSP11 Shares at the Effective Time by (ii) the fractional
interest.

          2.8 Dissenting Shares.  PSP11 Shares,  PSP11 Series B and C Shares and
AOPP  Shares held by a holder who has  demanded  and  perfected  his right to an
appraisal of such shares in accordance  with Section 1300 et seq. of the General
Corporation Law of California (the "GCLC") and who has not effectively withdrawn
or lost his right to appraisal  ("Dissenting  Shares")  shall not continue to be
owned by the holder  thereof or converted into or represent the right to receive
cash and/or PSP11 Shares,  but the holder thereof shall be entitled only to such
rights as are  granted  by  Section  1300 et seq.  of the GCLC.  Each  holder of
Dissenting Shares who becomes entitled to payment for PSP11 Shares, PSP11 Series
B and C Shares or AOPP  Shares  pursuant to these  provisions  of the GCLC shall
receive payment therefor from the Surviving Corporation in accordance therewith.
If any holder of PSP11  Shares,  PSP11  Series B and C Shares or AOPP Shares who
demands  appraisal  in  accordance  with  Section 1300 et seq. of the GCLC shall
effectively  withdraw  with the  consent of the  Surviving  Corporation  or lose
(through failure to perfect or otherwise) his right to appraisal with respect to
                                      

                                      A-4


PSP11  Shares,  PSP11  Series B and C Shares or AOPP  Shares,  such shares shall
automatically  be converted  into the right to receive PSP11 Shares  pursuant to
Section 2.1(b), 2.2(b) or 2.3(b) hereof, as the case may be.

          2.9  Assumption  of  AOPP  Options.   At  the  Effective   Time,  each
outstanding  option to purchase  AOPP Shares (an "AOPP  Option")  granted  under
AOPP's 1997 Stock Option and  Incentive  Plan (the "AOPP Plan") shall be assumed
by PSP11 and, whether vested or unvested,  shall be converted into, and shall be
deemed to  constitute,  an option to acquire,  on the same terms and  conditions
applicable  to the AOPP  Option,  the number of shares of PSP11  Shares that the
holder of the AOPP Option  would have  received in the Merger if the AOPP Option
had been exercised in full immediately prior to the Effective Time, irrespective
of whether the AOPP Option was in fact then exercisable (a "Converted  Option").
The  exercise  price  per share of a  Converted  Option  shall be the  aggregate
exercise  price  of the AOPP  Option  divided  by the  number  of  PSP11  Shares
purchasable upon exercise of the Converted  Option. As soon as practicable after
the  Effective  Time,  PSP11  shall  deliver to each holder of an AOPP Option an
appropriate  notice setting forth the holder's  rights pursuant  thereto.  PSP11
shall  comply with the terms of each AOPP Option and take all  corporate  action
necessary  to reserve  for  issuance  a  sufficient  number of PSP11  Shares for
delivery upon exercise of the Converted Options.

                                   ARTICLE III

          3.1 Headings.  The descriptive  headings  contained in the Sections of
this Agreement are for convenience of reference only and shall not affect in any
way the meaning or interpretation of this Agreement.

          3.2 Parties in Interest. This Agreement, and the rights, interests and
obligations  created by this  Agreement,  shall bind and inure to the benefit of
the parties and their  respective  successors and permitted  assigns,  and shall
confer  no  right,  benefit  or  interest  upon  any  other  person,   including
shareholders of the respective parties.

          3.3  Counterparts.  This  Agreement  may be  executed  in two or  more
counterparts,  each of which shall be deemed to be an original, but all of which
shall be considered one and the same agreement.

          3.4  Further  Action.  If at any time after the  Effective  Time,  the
Surviving Corporation shall determine that any assignments,  transfers, deeds or
other  assurances  are  necessary or desirable to vest,  perfect or confirm,  of
record or  otherwise,  in the  Surviving  Corporation,  title to any property or
rights  of AOPP,  the  officers  of  either  Constituent  Corporation  are fully
authorized  in the  name  of AOPP or  otherwise  to  execute  and  deliver  such
documents  and do all things  necessary  and proper to vest,  perfect or confirm
title to such property or rights in the Surviving Corporation.

          3.5 Governing Law. This  Agreement  shall be governed by and construed
in accordance with the laws of the State of California, without giving effect to
the principles of conflict of laws thereof.

                                      A-5



          3.6 Abandonment of Merger. The Constituent Corporations have the power
to abandon  the  Merger by mutual  written  consent  prior to the filing of this
Agreement with the California Secretary of State.


     IN WITNESS WHEREOF,  the parties have entered into this Agreement as of the
date first above written.


                                PUBLIC STORAGE PROPERTIES XI, INC.


                                 By:
                                    -----------------------------------
                                    B. Wayne Hughes
                                    Chairman of the Board of Directors 
                                    and Chief Executive Officer


                                 By:
                                    -----------------------------------
                                    Obren B. Gerich
                                    Secretary


                                 AMERICAN OFFICE PARK PROPERTIES, INC.


                                 By:
                                    -----------------------------------
                                    Ronald L. Havner, Jr.
                                    Chief Executive Officer



                                 By:
                                    -----------------------------------
                                    Mary Jayne Howard
                                    Assistant Secretary


                                      A-6