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                                                                    EXHIBIT 10.8





                                  July 30, 1998



Developers Diversified Realty Corporation
34555 Chagrin Boulevard
Moreland Hills, Ohio

     Re:  Voting Agreement

Ladies and Gentlemen:

     The undersigned understands that Developers Diversified Realty Corporation,
an Ohio corporation ("DDRC"), and American Industrial Properties REIT, a Texas
real estate investment trust ("AIP"), are entering into a Share Purchase
Agreement to be dated on or about the date hereof (the "Purchase Agreement"),
and, together with DDR Office Flex Corporation, a Delaware corporation, a Merger
Agreement to be dated on or about the date hereof (the "Merger Agreement" and,
together with the Purchase Agreement, the "Agreements"), providing for, among
other things, the purchase of common shares, $.10 par value per share, of AIP by
DDRC (the "Share Purchase"). Under the rules of the New York Stock Exchange,
consummation of the Share Purchase will require the approval of the shareholders
of AIP.

     The undersigned is a shareholder of AIP (the "Shareholder") and is entering
into this letter agreement at your request, in exchange for good and valuable
consideration, the receipt and sufficiency of which is hereby acknowledged, to
induce you to enter into the Agreements and to consummate the transactions
contemplated thereby.

     The Shareholder confirms its agreement with you as follows:

     1.   The Shareholder represents and warrants that Schedule I annexed hereto
          sets forth the shares of beneficial interest of AIP of which the
          Shareholder or any affiliate (as defined under the Securities Exchange
          Act of 1934, as amended) of the Shareholder controlled by the
          Shareholder (a "Controlled Affiliate") is the beneficial owner (the
          "Shares") and that the Shareholder and the Controlled Affiliates are
          on the date hereof the lawful owners of the number of Shares set forth
          in Schedule I, free and clear of all liens, charges, encumbrances,
          voting agreements and commitments of any kind, except as disclosed in
          Schedule I. Except for the Shares set forth in Schedule I, neither the
          Shareholder nor any Controlled Affiliate owns or holds any rights to
          acquire any additional shares of beneficial interest of AIP (other
          than pursuant to options or conversion rights with regard to any of
          the Shares, in each case as disclosed in Schedule I) or any interest
          therein or any


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Developers Diversified Realty Corporation
July 30, 1998
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          voting rights with respect to any such additional shares.

     2.   Until the earliest date referred to in Section 12, the Shareholder
          agrees that it will not, and will not permit any Controlled Affiliate
          to, contract to sell, sell or otherwise transfer or dispose of any of
          the Shares or any interest therein or securities convertible into
          shares of beneficial interest of AIP, or any voting rights with
          respect thereto, without your prior written consent.

     3.   The Shareholder agrees that, during the term of this letter agreement,
          neither it nor any Controlled Affiliate will take any action that AIP
          would at that time be prohibited from taking under Section 5.4 of the
          Purchase Agreement.

     4.   The Shareholder agrees that during the term of this letter agreement
          (a) all of the shares of beneficial interest of AIP beneficially owned
          by the Shareholder or any Controlled Affiliate, or over which the
          Shareholder or any Controlled Affiliate has voting power or control,
          directly or indirectly, including any such shares acquired after the
          date hereof at the record date for any meeting of shareholders of AIP
          called to consider and vote on the Share Purchase and the Agreements
          and the transactions contemplated thereby or any Competing Transaction
          (as such term is defined in the Purchase Agreement) will be voted by
          the Shareholder or such Controlled Affiliates, or any representative
          or proxy thereof, as applicable, in favor of the approval of the Share
          Purchase and the Agreements and the transactions contemplated thereby
          and (b) neither the Shareholder nor any Controlled Affiliate, nor any
          such representative or proxy will vote any such Shares in favor of any
          Competing Transaction.

     5.   The Shareholder agrees that the shares referred to in Section 4 above,
          owned at the record date for any meeting of shareholders of AIP called
          to consider and vote on the election of members of the Board of Trust
          Managers of the Trust (the "Board"), will be voted by the Shareholder
          or any Controlled Affiliate, or any representative or proxy thereof,
          as applicable, in favor of the approval of the election of the
          representatives of DDRC to the Board for so long as DDRC has the right
          to nominate members of the Board under the Purchase Agreement.

     6.   The Shareholder hereby appoints Marc A. Simpson to attend the special
          meeting of the shareholders of AIP held to consider and vote on


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Developers Diversified Realty Corporation
July 30, 1998
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          the Share Purchase and to vote the shares referred to in Section 4
          above, with all the power the Shareholder would possess if personally
          present, in favor of the approval of the Share Purchase, the
          Agreements and the transactions contemplated thereby. The Shareholder
          agrees to execute, and to cause each Controlled Affiliate to execute,
          such proxies and other instruments, and to take and to cause each
          Controlled Affiliate to take such actions, as may be necessary to
          cause all of those shares to be so voted.

     7.   The Shareholder has all necessary power and authority to enter into
          this letter agreement. This letter agreement is the legal, valid and
          binding agreement of the Shareholder, and is enforceable against the
          Shareholder in accordance with its terms, subject to applicable
          bankruptcy, insolvency, fraudulent conveyance, reorganization,
          moratorium and similar laws affecting creditors' rights and remedies
          generally and to general principles of equity. This letter agreement
          shall inure to the benefit of the parties hereto and the successors
          and assigns of DDRC.

     8.   The Shareholder agrees that damages are an inadequate remedy for the
          breach by Shareholder of any term or condition of this letter
          agreement and that you shall be entitled to a temporary restraining
          order and preliminary and permanent injunctive relief in order to
          enforce our agreements herein.

     9.   Except to the extent that the laws of the jurisdiction of organization
          of any party hereto, or any other jurisdiction, are mandatorily
          applicable to matters arising under or in connection with this letter
          agreement, this letter agreement shall be governed by the laws of the
          State of Ohio. All actions and proceedings arising out of or relating
          to this letter agreement shall be heard and determined in any United
          States District Court sitting in the Northern District of Ohio.

     10.  Each of the parties hereto irrevocably submits to the exclusive
          jurisdiction of any United States District Court located in the
          Northern District of Ohio, for the purpose of any action or proceeding
          arising out of or relating to this letter agreement and each of the
          parties hereto irrevocably agrees that all claims in respect of such
          action or proceeding may be heard and determined exclusively in any
          federal court sitting in the Northern District of Ohio. Each of the
          parties hereto agrees that a final judgment in any action or
          proceeding shall be conclusive and may


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Developers Diversified Realty Corporation
July 30, 1998
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          be enforced in other jurisdictions by suit on the judgment or in any
          other manner provided by law.

     Shareholder hereby irrevocably appoints CT Corporation as its lawful agent
in and for the State of Ohio, for and in its behalf, to accept and acknowledge
service of, and upon whom may be served, all necessary processes in any action,
suit, or proceeding arising under this Agreement that may be had or brought
against it in any federal court in the Northern District of Ohio, such service
of process or notice, or the acceptance thereof by said agent endorsed thereon,
to have the same force and effect as if served upon such corporation or
individual. Nothing in this Section 10 shall affect the right of any party
hereto to serve legal process in any other manner permitted by law. Shareholder
hereby waives all defenses of improper venue and forum non conveniens with
respect to any action, suit, or proceeding brought in the any United States
District Court located in the Northern District of Ohio and arising under this
letter agreement.

     11.  This letter agreement constitutes the entire agreement between the
          parties hereto with respect to the matters covered hereby and
          supersedes all prior agreements, understandings or representations
          between the parties, written or oral, with respect to the subject
          matter hereof.

     12.  This letter agreement and the proxy granted pursuant to Section 6
          hereof shall become effective upon the execution and delivery of the
          Agreements by the respective parties thereto. Except as otherwise
          provided herein, this letter agreement and the proxy granted pursuant
          to Section 6 hereof shall terminate automatically, without the need
          for any notice or other action by either party upon the earliest of
          (i) the date on which the Purchase Agreement and the Merger Agreement
          are terminated, (ii) the Second Closing Date, as defined in the
          Purchase Agreement, and (iii) the date that is 240 days after the date
          hereof.

     13.  Each of the parties hereto intends that AIP shall be a third party
          beneficiary of this letter agreement, and shall be entitled to the
          benefits hereof and shall have the ability to enforce the rights
          granted to DDRC herein as fully as if it were a signatory of this
          letter agreement.

     14.  Notwithstanding anything to the contrary contained herein, neither AIP
          nor any representative of the Shareholder serving on the Board of
          Trust Managers of AIP shall be deemed to be a Controlled Affiliate.



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Developers Diversified Realty Corporation
July 30, 1998
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     Please confirm that the foregoing correctly states the understanding
between us by signing and returning to me a counterpart hereof.

                                    Morgan Stanley Asset Management Inc., on
                                    behalf of certain of its clients with
                                    respect to shares of AIP over which it
                                    exercises investment discretion, and MS Real
                                    Estate Special Situations, Inc.


                                    By: /s/ Russell Platt
                                        --------------------------------------
                                    Name: Russell Platt
                                         -------------------------------------
                                    Title: Managing Director
                                          ------------------------------------



Confirmed on the date
first above written

Developers Diversified Realty Corporation


By: /s/ Scott A. Wolstein
   -------------------------------
Name: Scott A. Wolstein
     -----------------------------
Title: President
      ----------------------------



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                                   Schedule I

                   Ownership of Shares of Beneficial Interest


Owned Beneficially (including Options to Purchase Shares)

Trust Common Shares                 1,999,653