EXHIBIT 3.1F

                         Certificate of Incorporation
                                      of
                              IM San Diego, Inc.


FIRST: The name of the corporation is IM San Diego, Inc.

SECOND: The registered office of the Corporation in the State of Delaware is
located at 32 Loockerman Square, Suite L-100, Dover, Kent County, Delaware
19901; and the name of its registered agent at such address is The Prentice-Hall
Corporation System, Inc.

THIRD: The purpose of the Corporation is to engage, anywhere in the world, in
any lawful act or activity for which corporations may be organized under the
General Corporation Law of Delaware; and to possess and exercise all powers and
privileges granted by the General Corporation Law of Delaware.

FOURTH: The total number of shares of capital stock which the Corporation is
authorized to issue is 1,000 (one thousand) shares, all of which shall be shares
of Common Stock of the par value of $1.00 per share.

FIFTH: The name and mailing address of the incorporator is as follows:

      Name                          Mailing Address

Garry B. Watzke                     745 Atlantic Avenue, Boston, MA 02111

SIXTH: The name and mailing address of the person who is to serve as sole
director until the first meeting of stockholders, or until his successor is
elected and qualified, whichever first occurs, is as follows:

C. Richard Reese                    745 Atlantic Avenue, Boston, MA 02111

SEVENTH: For the management of the business and for the conduct of the affairs
of the Corporation, and in further definition, limitation and regulation of the
powers of its directors and stockholders, it is further provided:

1.    The number of directors of the Corporation shall be as prescribed in the
      By-laws of the Corporation but such number may from time to time be
      increased or decreased in such manner as may be prescribed by the By-laws.
      In no event shall the number of Directors be less than the minimum number
      prescribed by law.

2.    In furtherance and not in limitation of the powers conferred by the laws
      of the State of Delaware, the Board of Directors is expressly authorized
      and empowered:






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      (a)   Subject to the applicable provisions of the By-laws then in effect,
            to determine, from time to time, whether and to what extent and at
            what times and places and under what conditions and regulations the
            accounts and books of the Corporation, or any of them, shall be open
            to the inspection of the stockholders, and no stockholder shall have
            any right to inspect any account or document of the Corporation,
            except as conferred by the laws of the State of Delaware, unless and
            until authorized so to do by resolution of the Board of Directors or
            of the stockholders of the Corporation.

      (b)   Without the assent or vote of the stockholders to authorize and
            issue obligations of the Corporation, secured or unsecured, to
            include therein such provisions as to redeemability, convertibility
            or otherwise, as the Board of Directors, in its sole discretion, may
            determine, and to authorize the mortgaging or pledging, as security
            therefor, of any property of the Corporation, real or personal,
            including after-acquired property.

      (c)   To establish a bonus, profit-sharing or other types of incentive or
            compensation plans for the employees (including officers and
            Directors) of the Corporation and to fix the amount of profits to be
            distributed or shared and to determine the persons to participate in
            any such plans and the amounts their respective participants.

      (d)   To make, alter, amend or repeal the By-laws of the Corporation.

      (e)   To determine for any purpose and in any manner not inconsistent with
            the other provisions of this Certificate of Incorporation the amount
            of the gross assets, of the liabilities, of the net assets or of the
            net profits of the Corporation as the same exist or shall have
            existed at any time or for any period or periods, and to create,
            increase, abolish or reduce any reserve or reserves for accrued,
            accruing or contingent liabilities or expenses, including taxes and
            other charges.

      In addition to the powers and authorities hereinbefore or by statute
      expressly conferred upon it, the Board of Directors may exercise all such
      powers and do all such acts and things as may be exercised or done by the
      Corporation, subject, nevertheless, to the provisions of the laws of the
      State of Delaware, of the Certificate of Incorporation and of the By-laws
      of the Corporation.

3.    Any Director or any officer elected or appointed by the stockholders or by
      the Board of Directors may be removed at any time in such manner as shall
      be provided in the By-laws of the Corporation.

4.    In the absence of fraud, no contract or other transaction between the
      Corporation and any other corporation, and no act of the Corporation,
      shall in any way be affected or invalidated by the fact that any of the
      Directors of the Corporation are pecuniarily or otherwise interested in,
      or are directors or officers of, such other corporation and, in the
      absence of fraud, any Director may be a member, may be a party to, or may
      be


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      pecuniarily or otherwise interested in, any contract or transaction of the
      Corporation; provided, in any case, that the fact that he or such firm is
      so interested shall be disclosed or shall have been known to the Board of
      Directors or a majority thereof; and any Director of the Corporation who
      is also a director or officer of any such other corporation, or who is
      also interested, may be counted in determining the existence of a quorum
      at any meeting of the Board of Directors of the Corporation which shall
      authorize any such Contract, act or transaction and may vote thereat to
      authorize any such contract, act or transaction, with like force and
      effect as if he were not such director or officer of such corporation, or
      not so interested.

5.    Any contract, act or transaction of the Corporation or of the Directors
      may be ratified by a vote of a majority of the shares having voting powers
      at any meeting of stockholders, or at any special meeting called for such
      purpose, and such ratification shall, so far as permitted by law and by
      this Certificate of Incorporation, be as valid and as binding as though
      ratified by every stockholder of the Corporation.

6.    No director of the Corporation shall be liable to any person on account of
      any action undertaken by him as such director in reliance in good faith
      upon the existence of any fact or circumstance reported or certified to
      the Board of Directors by any officer of the Corporation or by any
      independent auditor, engineer, or consultant retained or employed as such
      by the Board of Directors.

7.    Meetings of the stockholders may be held without the State of Delaware, if
      the Bylaws so provide. The books of the Corporation may be kept (subject
      to any statutory provision) outside the State of Delaware at such place or
      places as may be from time to time designated by the Board of Directors or
      in the By-laws of the Corporation. Elections of directors need not be by
      ballot unless the By-laws shall otherwise provide.

EIGHTH: Whenever a compromise or arrangement is proposed between the Corporation
and its creditors or any class of them and/or between the Corporation and its
stockholders or any class of them, any court of equitable jurisdiction within
the State of Delaware may, on the application in a summary way of the
Corporation or of any creditor or stockholder thereof or on the application of
any receiver or receivers appointed for the Corporation under the provisions of
Section 291 of Title 8 of the Delaware Code or on the application of trustees in
dissolution or of any receiver or receivers appointed for the Corporation under
the provisions of Section 279 of Title 8 of the Delaware Code, order a meeting
of the creditors or class of creditors, and/or of all the stockholders or class
of stockholders, of the Corporation, as the case may be, to be summoned in such
manner as the said court directs. If a majority in number representing
three-fourths in value of the creditors or class of creditors, and/or of the
stockholders or class of stockholders of the Corporation, as the case may be,
agree to any compromise or arrangement and to any reorganization of the
Corporation as consequence of such compromise or arrangement, the said
compromise or arrangement and the said reorganization shall, if sanctioned by
the court to which the said application has been made, be binding on all the
creditors or class of the creditors, and/or on all the stockholders or class of
stockholders, of the Corporation, as the case may be, and also on the
Corporation.






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NINTH: No director shall be personally liable to the Corporation or any
stockholder for monetary damages for breach of fiduciary duty as a director,
except, in addition to any and all other requirements for such liability, (i)
for any breach of such director's duty of loyalty to the Corporation or its
stockholders, (ii) for acts or omissions not in good faith or which involve
intentional misconduct or a knowing violation of law, (iii) to the extent
provided under Section 174 of Title 8 of the Delaware Code (relating to the
General Corporation Law of the State of Delaware ) or any amendment thereto or
successor provision thereto, or (iv) for any transaction for which such director
derived an improper personal benefit. Neither the amendment nor repeal of this
Article NINTH, nor the adoption of any provision of this Certificate of
Incorporation inconsistent with the Article NINTH, shall eliminate or reduce the
effect of this Article NINTH in respect of any matter occurring, or any cause of
action, suit or claim that, but for this Article NINTH, would accrue or arise
prior to such amendment, repeal, or adoption of an inconsistent provision.

TENTH: The stockholders of the Corporation shall not be personally liable for
the payment of the Corporation's debts.

ELEVENTH: The Corporation shall indemnify, defend and hold harmless any person
who was or is a party, or is threatened to be made a party, to any threatened,
pending or completed action, suit or proceeding, whether civil, criminal,
administrative, investigative or other, including appeals, by reason of the fact
that he or she is or was a director, officer, employee or agent of the
Corporation, or is or was serving at the request of the Corporation as a
director, trustee, officer, employer or agent of any corporation, partnership,
joint venture, trust or other enterprise, including service with respect to
employee benefit plans, to the fullest extent authorized by Section 145 of the
Delaware General Corporation Law, as amended from time to time, against all
expenses, liabilities and losses (including attorneys' fees, judgment, fines,
ERISA excise taxes and penalties and amounts paid or to be paid in settlement)
reasonably incurred or suffered by such person in connection therewith;
provided, however, that, except with respect to proceedings seeking to enforce
the rights to indemnification granted herein, the Corporation shall indemnify
any such person seeking indemnification in connection with a proceeding (or part
thereof) initiated by such person only if the proceeding (or part thereof) was
authorized by the Board of Directors of the Corporation. Without limiting the
generality or the effect of the foregoing, the Corporation may enter into one or
more agreements with any person which provide for indemnification greater or
different than that provided in this Article ELEVENTH. Any repeal or
modification of the provisions of this Article ELEVENTH, or the adoption of any
provision inconsistent herewith, shall not adversely affect any right or
protection existing hereunder immediately prior to such repeal, modification or
adoption of an inconsistent provision. Notwithstanding the foregoing, all
indemnification provided for in this Article ELEVENTH shall not be deemed
exclusive of any other rights to which those entitled to receive indemnification
or reimbursement hereunder may be entitled under any By-law of the Corporation,
agreement, vote of stockholders or disinterested directors or otherwise.

TWELFTH: From time to time any of the provisions of this Certificate of
Incorporation may be amended, altered or repealed, and other provisions
authorized by the laws of the State of Delaware at the time in force may be
added or inserted in the manner and at the time prescribed by said laws, and all
rights at any time conferred upon the stockholders of




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the Corporation by this Certificate of Incorporation are granted subject to the
provisions of this Article TWELFTH.

      IN WITNESS WHEREOF, I have hereunto set my hand and seal this 23rd day of
September, 1993.


                                /s/ Garry B. Watzke
                                -------------------
                                    Garry B. Watzke
                                    Sole Incorporator