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                                                                    Exhibit 10.3


                           QUALIFIED BORROWER GUARANTY

            UNCONDITIONAL GUARANTY OF PAYMENT (this "Guaranty"), is made as of
December 11, 2002 by AMB PROPERTY, L.P., a Delaware limited partnership (the
"Guarantor") for the benefit of JPMORGAN CHASE BANK, as Administrative Agent
and J.P. MORGAN EUROPE LIMITED, as Administrative Agent (collectively, the
"Administrative Agent") for the banks (the "Banks") that are from time to time
parties to that certain Amended and Restated Revolving Credit Agreement (the
"Credit Agreement"), dated as of December 11, 2002 among the Guarantor, the
banks listed on the signature pages thereof, the Administrative Agent, Bank of
America, N.A., as Syndication Agent, J.P. Morgan Securities Inc. and Banc of
America Securities LLC, as Joint Lead Arrangers and Joint Bookrunners, Bank One,
NA, Commerzbank Aktiengesellschaft New York and Grand Cayman Branches, and
Wachovia Bank, N.A., as Documentation Agents, PNC Bank, National Association,
The Bank of Nova Scotia, acting through its San Francisco Agency, and Wells
Fargo Bank, N.A., as Managing Agents, and Keybank National Association, as
Co-Agent.

            Capitalized terms not otherwise defined in this Guaranty shall have
the meanings ascribed to them in the Credit Agreement.

                              W I T N E S S E T H:

            WHEREAS, pursuant to the terms of the Credit Agreement, a Qualified
Borrower may request that the Banks make one or more loans (each, a "Loan") to
the Qualified Borrower, to be guaranteed by Guarantor by this Guaranty and to be
evidenced by Qualified Borrower Notes (collectively, the "Note"), payable by the
Qualified Borrower to the order of the Banks.

            WHEREAS, this Guaranty is the "Qualified Borrower Guaranty" referred
to in the Credit Agreement;

            WHEREAS, in order to induce the Administrative Agent and the Banks
to make one or more Loans to one or more Qualified Borrowers, and to satisfy one
of the conditions contained in the Credit Agreement with respect thereto, the
Guarantor has agreed to enter into this Guaranty.

            NOW THEREFORE, in consideration of the premises and the direct and
indirect benefits to be derived from the making of the Loans by the Banks to
Qualified Borrowers, and for other good and valuable consideration, the receipt
and sufficiency of which is hereby acknowledged, Guarantor hereby agrees as
follows:

            i.    Guarantor, on behalf of itself and its successors and assigns,
hereby irrevocably, absolutely, and unconditionally guarantees the full and
punctual payment when due, whether at stated maturity or otherwise, of all
obligations of each and every Qualified Borrower now or hereafter existing under
the Note (whether executed and delivered simultaneously
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herewith or subsequently), or under any of the other Loan Documents (such
obligations, whenever arising, being the "Guaranteed Obligations"), and any and
all reasonable costs and expenses (including, without limitation, reasonable
attorneys' fees and disbursements) incurred by the Administrative Agent in
enforcing its rights under this Guaranty.

            ii.   It is agreed that the obligations of Guarantor hereunder are
primary and this Guaranty shall be enforceable against Guarantor and its
successors and assigns without the necessity for any suit or proceeding of any
kind or nature whatsoever brought by the Administrative Agent against the
relevant Qualified Borrower or its respective successors or assigns or any other
party or against any security for the payment and performance of the Guaranteed
Obligations and without the necessity of any notice of non-payment or
non-observance or of any notice of acceptance of this Guaranty or of any notice
or demand to which Guarantor might otherwise be entitled (including, without
limitation, diligence, presentment, notice of maturity, extension of time,
change in nature or form of the Guaranteed Obligations, acceptance of further
security, release of further security, imposition or agreement arrived at as to
the amount of or the terms of the Guaranteed Obligations, notice of adverse
change in such Qualified Borrower's financial condition and any other fact which
might materially increase the risk to Guarantor), all of which Guarantor hereby
expressly waives; and Guarantor hereby expressly agrees that the validity of
this Guaranty and the obligations of the Guarantor hereunder shall in no way be
terminated, affected, diminished, modified or impaired by reason of the
assertion of or the failure to assert by the Administrative Agent against such
Qualified Borrower or its respective successors or assigns, any of the rights or
remedies reserved to the Administrative Agent pursuant to the provisions of the
Loan Documents. Guarantor hereby agrees that any notice or directive given at
any time to the Administrative Agent which is inconsistent with the waiver in
the immediately preceding sentence shall be void and may be ignored by the
Administrative Agent, and, in addition, may not be pleaded or introduced as
evidence in any litigation relating to this Guaranty for the reason that such
pleading or introduction would be at variance with the written terms of this
Guaranty, unless the Administrative Agent has specifically agreed otherwise in a
writing, signed by a duly authorized officer. Guarantor specifically
acknowledges and agrees that the foregoing waivers are of the essence of this
transaction and that, but for this Guaranty and such waivers, the Banks would
not make Loans and the Fronting Bank would not issue Letters of Credit on behalf
of any Qualified Borrower.

            iii.  Guarantor hereby waives, and covenants and agrees that it will
not at any time insist upon, plead or in any manner whatsoever claim or take the
benefit or advantage of, any and all appraisal, valuation, stay, extension,
marshaling-of-assets or redemption laws, or right of homestead or exemption,
whether now or at any time hereafter in force, which may delay, prevent or
otherwise affect the performance by Guarantor of its obligations under, or the
enforcement by the Administrative Agent of, this Guaranty. Guarantor further
covenants and agrees not to set up or claim any defense, counterclaim, offset,
set-off or other objection of any kind to any action, suit or proceeding in law,
equity or otherwise, or to any demand or claim that may be instituted or made by
the Administrative Agent other than the defense of the actual timely payment and
performance by the relevant Qualified Borrower of the Guaranteed Obligations
hereunder; provided, however, that the foregoing shall not be deemed a waiver of
Guarantor's right


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to assert any compulsory counterclaim, if such counterclaim is compelled under
local law or rule of procedure, nor shall the foregoing be deemed a waiver of
Guarantor's right to assert any claim which would constitute a defense, setoff,
counterclaim or crossclaim of any nature whatsoever against Administrative Agent
or any Bank in any separate action or proceeding. Guarantor represents, warrants
and agrees that, as of the date hereof, its obligations under this Guaranty are
not subject to any counterclaims, offsets or defenses of any kind against the
Administrative Agent, the Banks or the Fronting Bank.

            iv.   The provisions of this Guaranty are for the benefit of the
Administrative Agent on behalf of the Banks and their successors and permitted
assigns, and nothing herein contained shall impair as between any Qualified
Borrower and the Administrative Agent the obligations of such Qualified Borrower
under the Loan Documents.

            v.    This Guaranty shall be a continuing, unconditional and
absolute guaranty and the liability of Guarantor hereunder shall in no way be
terminated, affected, modified, impaired or diminished by reason of the
happening, from time to time, of any of the following, all without notice or the
further consent of Guarantor:

                  (1)   any assignment, amendment, modification or waiver of or
                        change in any of the terms, covenants, conditions or
                        provisions of any of the Guaranteed Obligations or the
                        Loan Documents or the invalidity or unenforceability of
                        any of the foregoing; or

                  (2)   any extension of time that may be granted by the
                        Administrative Agent to any Qualified Borrower, any
                        guarantor, or their respective successors or assigns,
                        heirs, executors, administrators or personal
                        representatives; or

                  (3)   any action which the Administrative Agent may take or
                        fail to take under or in respect of any of the Loan
                        Documents or by reason of any waiver of, or failure to
                        enforce any of the rights, remedies, powers or
                        privileges available to the Administrative Agent under
                        this Guaranty or available to the Administrative Agent
                        at law, equity or otherwise, or any action on the part
                        of the Administrative Agent granting indulgence or
                        extension in any form whatsoever; or

                  (4)   any sale, exchange, release, or other disposition of any
                        property pledged, mortgaged or conveyed, or any property
                        in which the Administrative Agent and/or the Banks have
                        been granted a lien or security interest to secure any
                        indebtedness of any Qualified Borrower to the
                        Administrative Agent and/or the Banks; or

                  (5)   any release of any person or entity who may be liable in
                        any manner for the payment and collection of any
                        amounts owed by any


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                        Qualified Borrower to the Administrative Agent and/or
                        the Banks; or

                  (6)   the application of any sums by whomsoever paid or
                        however realized to any amounts owing by any Qualified
                        Borrower to the Administrative Agent and/or the Banks
                        under the Loan Documents in such manner as the
                        Administrative Agent shall determine in its sole
                        discretion; or

                  (7)   any Qualified Borrower's or the Guarantor's voluntary or
                        involuntary liquidation, dissolution, sale of all or
                        substantially all of their respective assets and
                        liabilities, appointment of a trustee, receiver,
                        liquidator, sequestrator or conservator for all or any
                        part of any Qualified Borrower's or Guarantor's assets,
                        insolvency, bankruptcy, assignment for the benefit of
                        creditors, reorganization, arrangement, composition or
                        readjustment, or the commencement of other similar
                        proceedings affecting any Qualified Borrower or
                        Guarantor or any of the assets of any of them,
                        including, without limitation, (i) the release or
                        discharge of any Qualified Borrower or Guarantor from
                        the payment and performance of their respective
                        obligations under any of the Loan Documents by operation
                        of law, or (ii) the impairment, limitation or
                        modification of the liability of any Qualified Borrower
                        or Guarantor in bankruptcy, or of any remedy for the
                        enforcement of the Guaranteed Obligations under any of
                        the Loan Documents, or Guarantor's liability under this
                        Guaranty, resulting from the operation of any present or
                        future provisions of the Bankruptcy Code or other
                        present or future federal, state or applicable statute
                        or law or from the decision in any court; or

                  (8)   any improper disposition by any Qualified Borrower of
                        the proceeds of the Loans, it being acknowledged by
                        Guarantor that the Administrative Agent shall be
                        entitled to honor any request made by any Qualified
                        Borrower for a disbursement of such proceeds and that
                        the Administrative Agent shall have no obligation to see
                        the proper disposition by such Qualified Borrower of
                        such proceeds.

                  (9)   Guarantor hereby agrees that if at any time all or any
                        part of any payment at any time received by the
                        Administrative Agent from any Qualified Borrower under
                        any of the Notes or other Loan Documents or Guarantor
                        under or with respect to this Guaranty is or must be
                        rescinded or returned by the Administrative Agent for
                        any reason whatsoever (including, without limitation,
                        the insolvency, bankruptcy or reorganization of any
                        Qualified Borrower or


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                        Guarantor), then Guarantor's obligations hereunder
                        shall, to the extent of the payment rescinded or
                        returned, be deemed to have continued in existence
                        notwithstanding such previous receipt by the
                        Administrative Agent, and Guarantor's obligations
                        hereunder shall continue to be effective or reinstated,
                        as the case may be, as to such payment, as though such
                        previous payment to the Administrative Agent had never
                        been made.

                  (10)  Until this Guaranty is terminated pursuant to the terms
                        hereof, the Guarantor (i) shall have no right of
                        subrogation against any Qualified Borrower or any
                        entity comprising same by reason of any payments or acts
                        of performance by Guarantor in compliance with the
                        obligations of Guarantor hereunder; (ii) hereby waives
                        any right to enforce any remedy which Guarantor now or
                        hereafter shall have against any Qualified Borrower or
                        any entity comprising same by reason of any one or more
                        payment or acts of performance in compliance with the
                        obligations of Guarantor hereunder; and (iii) from and
                        after an Event of Default (as defined in the Credit
                        Agreement) subordinates any liability or indebtedness
                        of any Qualified Borrower or any entity comprising same
                        now or hereafter held by Guarantor to the obligations of
                        each Qualified Borrower under the Loan Documents.

            vi.   Guarantor hereby represents, warrants and covenants on its own
behalf to the Administrative Agent with the knowledge that the Administrative
Agent is relying upon the same, as follows:

                   (1)  Guarantor will be familiar with the financial condition
                        of each Qualified Borrower;

                   (2)  Guarantor has determined that it is in its best interest
                        to enter into this Guaranty;

                   (3)  this Guaranty is necessary and convenient to the
                        conduct, promotion and attainment of Guarantor's
                        business, and is in furtherance of Guarantor's business
                        purposes;

                   (4)  the benefits to be derived by Guarantor from each
                        Qualified Borrower's access to funds made possible by
                        the Loan Documents are at least equal to the obligations
                        of Guarantor undertaken pursuant to this Guaranty;

                   (5)  the Guarantor is solvent and has full partnership power
                        and legal right to enter into this Guaranty and to
                        perform its obligations


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                        under the terms hereof and (i) Guarantor is organized
                        and validly existing under the laws of its state of
                        formation, (ii) Guarantor has complied with all
                        provisions of applicable law in connection with all
                        aspects of this Guaranty, and (iii) the person executing
                        this Guaranty on behalf of Guarantor has all the
                        requisite power and authority to execute and deliver
                        this Guaranty; and

                   (6)  this Guaranty has been duly executed by Guarantor and
                        constitutes the legal, valid and binding obligation of
                        Guarantor, enforceable against it in accordance with its
                        terms except as enforceability may be limited by
                        applicable insolvency, bankruptcy or other laws
                        affecting creditors' rights generally or general
                        principles of equity whether such enforceability is
                        considered in a proceeding in equity or at law.

      The foregoing representations and warranties shall be deemed to be made as
of the date hereof and as the date of the making any Loan or the issuance of any
Letter of Credit to or for the account on any Qualified Borrower.

            vii.  Each of Guarantor and the Administrative Agent acknowledges
and agrees that this Guaranty is a guaranty of payment and not of collection and
enforcement in respect of any obligations which may accrue to the Administrative
Agent and/or the Banks from each Qualified Borrower under the provisions of any
Loan Document.

            viii. Subject to the terms and conditions of the Credit Agreement,
and in conjunction therewith, the Administrative Agent may assign any or all of
its rights under this Guaranty.

            ix.   Guarantor agrees, upon the written request of the
Administrative Agent, to execute and deliver to the Administrative Agent, from
time to time, any modification or amendment hereto or any additional instruments
or documents reasonably considered necessary by the Administrative Agent or its
counsel to cause this Guaranty to be, become or remain valid and effective in
accordance with its terms, provided, that, any such modification, amendment,
additional instrument or document shall not increase Guarantor's obligations or
diminish its rights hereunder and shall be reasonably satisfactory as to form to
Guarantor and to Guarantor's counsel.

            x.    The representations and warranties of the Guarantor set forth
in this Guaranty shall survive until this Guaranty shall terminate in accordance
with the terms hereof.

            xi.   This Guaranty together with the Credit Agreement, each Note
now or hereafter executed and delivered by any Qualified Borrower, and the other
Loan Documents contain the entire agreement among the parties with respect to
the subject matter hereof and supersedes all prior agreements relating to such
subject matter and may not be modified,


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amended, supplemented or discharged except by a written agreement signed by
Guarantor and the Administrative Agent.

            xii.  If all or any portion of any provision contained in this
Guaranty shall be determined to be invalid, illegal or unenforceable in any
respect for any reason, such provision or portion thereof shall be deemed
stricken and severed from this Guaranty and the remaining provisions and
portions thereof shall continue in full force and effect.

            xiii. This Guaranty may be executed in counterparts which together
shall constitute the same instrument.

            xiv.  All notices, requests and other communications to any party
hereunder shall be in writing (including bank wire, telex, facsimile
transmission followed by telephonic confirmation or similar writing) and shall
be addressed to such party at the address set forth below or to such other
address as may be identified by any party in a written notice to the others:

If to a
Qualified Borrower:              At the address identified therefor by Borrower
                                 at the time such Qualified Borrower delivers
                                 its Note or, if no such address is so
                                 identified, at the address of Borrower set
                                 forth in the Credit Agreement for notices.

If to
Guarantor:                       At the address set forth in the Credit
                                 Agreement for notices.

With Copies of
Notices to the
Qualified Borrower
or Guarantor to:                 Piper Rudnick
                                 203 North LaSalle Street, Suite 1800
                                 Chicago, Illinois 60601
                                 Attention: James M. Phipps, Esq.

If to the Administrative Agent:  JPMorgan Chase Bank
                                 270 Park Avenue
                                 4th Floor
                                 New York, New York 10017
                                 Attention: John F. Mix, Vice President

With Copies to:                  JPMorgan Chase Bank
                                 1 Chase Manhattan Plaza
                                 8th Floor
                                 New York, New York 10081


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                                 Attn: Evan Repousis

With Copies to:                  Skadden, Arps, Slate, Meagher & Flom
                                 4 Times Square
                                 New York, New York 10036
                                 Attention:  Martha Feltenstein, Esq.

            Each such notice, request or other communication shall be effective
(i) if given by telex or facsimile transmission, when such telex or facsimile is
transmitted to the telex number or facsimile number specified in this Section
and the appropriate answerback or facsimile confirmation is received, (ii) if
given by certified registered mail, return receipt requested, with first class
postage prepaid, addressed as aforesaid, upon receipt or refusal to accept
delivery, (iii) if given by a nationally recognized overnight carrier, 24 hours
after such communication is deposited with such carrier with postage prepaid for
next day delivery, or (iv) if given by any other means, when delivered at the
address specified in this Section.

            xv.   This Guaranty shall be binding upon Guarantor and its
successors and assigns and shall inure to the benefit of the Administrative
Agent and its successors and assigns.

            xvi.  The failure of the Administrative Agent to enforce any right
or remedy hereunder, or promptly to enforce any such right or remedy, shall not
constitute a waiver thereof, nor give rise to any estoppel against the
Administrative Agent, nor excuse Guarantor from its obligations hereunder. Any
waiver of any such right or remedy to be enforceable against the Administrative
Agent must be expressly set forth in a writing signed by the Administrative
Agent.

            xvii.             (1)   THIS GUARANTY AND THE RIGHTS AND OBLIGATIONS
                                    OF THE PARTIES HEREUNDER SHALL BE CONSTRUED
                                    IN ACCORDANCE WITH AND BE GOVERNED BY THE
                                    LAWS OF THE STATE OF NEW YORK.

                   (2)  Any legal action or proceeding with respect to this
                        Guaranty and any action for enforcement of any judgment
                        in respect thereof may be brought in the courts of the
                        State of New York or of the United States of America for
                        the Southern District of New York, and, by execution and
                        delivery of this Guaranty, Guarantor hereby accepts for
                        itself and in respect of its property, generally and
                        unconditionally, the non-exclusive jurisdiction of the
                        aforesaid courts and appellate courts from any thereof.
                        Guarantor irrevocably consents to the service of process
                        out of any of the aforementioned courts in any such
                        action or proceeding by the mailing of copies thereof by
                        registered or certified mail, postage prepaid, to
                        Guarantor at the address for notices set forth herein.
                        Guarantor hereby irrevocably


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                        waives any objection which it may now or hereafter have
                        to the laying of venue of any of the aforesaid actions
                        or proceedings arising out of or in connection with this
                        Guaranty brought in the courts referred to above and
                        hereby further irrevocably waives and agrees not to
                        plead or claim in any such court that any such action or
                        proceeding brought in any such court has been brought in
                        an inconvenient forum. Nothing herein shall affect the
                        right of the Administrative Agent to serve process in
                        any other manner permitted by law or to commence legal
                        proceedings or otherwise proceed against Guarantor in
                        any other jurisdiction.

                   (3)  EACH OF THE GUARANTOR AND THE ADMINISTRATIVE AGENT
                        HEREBY WAIVES ITS RIGHTS TO A JURY TRIAL OF ANY AND ALL
                        CLAIMS OR CAUSES OF ACTION BASED UPON OR ARISING OUT OF
                        THIS GUARANTY. IT IS HEREBY ACKNOWLEDGED BY GUARANTOR
                        THAT THE WAIVER OF A JURY TRIAL IS A MATERIAL INDUCEMENT
                        FOR THE ADMINISTRATIVE AGENT TO ACCEPT THIS GUARANTY AND
                        THAT THE LOANS MADE BY THE BANKS ARE MADE IN RELIANCE
                        UPON SUCH WAIVER. GUARANTOR FURTHER WARRANTS AND
                        REPRESENTS THAT SUCH WAIVER HAS BEEN KNOWINGLY AND
                        VOLUNTARILY MADE, FOLLOWING CONSULTATION WITH LEGAL
                        COUNSEL. IN THE EVENT OF LITIGATION, THIS GUARANTY MAY
                        BE FILED BY THE ADMINISTRATIVE AGENT IN COURT AS A
                        WRITTEN CONSENT TO A NON-JURY TRIAL.

                   (4)  Guarantor hereby further covenants and agrees with the
                        Administrative Agent that Guarantor may be joined in
                        any action against the Qualified Borrower in connection
                        with the Loan Documents and that recovery may be had
                        against Guarantor in such action or in any independent
                        action against Guarantor (with respect to the Guaranteed
                        Obligations), without the Administrative Agent first
                        pursuing or exhausting any remedy or claim against the
                        Qualified Borrower or its successors or assigns.
                        Guarantor also agrees that, in an action brought with
                        respect to the Guaranteed Obligations in any
                        jurisdiction, it shall be conclusively bound by the
                        judgment in any such action by the Administrative Agent
                        (wherever brought) against any Qualified Borrower or its
                        successors or assigns, as if Guarantor were a party to
                        such action, even though Guarantor was not joined as
                        parties in such action.


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                   (5)  Guarantor hereby agrees to pay all reasonable expenses
                        (including, without limitation, attorneys' fees and
                        disbursements) which may be incurred by the
                        Administrative Agent in connection with the enforcement
                        of its rights under this Guaranty, whether or not suit
                        is initiated.

            xviii. Subject to the terms of Section 5(i) hereof, this Guaranty
shall terminate and be of no further force or effect upon the full performance
and payment of the Guaranteed Obligations hereunder. Upon termination of this
Guaranty in accordance with the terms of this Guaranty, the Administrative Agent
promptly shall deliver to Guarantor such documents as Guarantor or Guarantor's
counsel reasonably may request in order to evidence such termination.

            xix.  All of the Administrative Agent's rights and remedies under
each of the Loan Documents or under this Guaranty are intended to be distinct,
separate and cumulative and no such right or remedy therein or herein mentioned
is intended to be in exclusion of or a waiver of any other right or remedy
available to the Administrative Agent.


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            IN WITNESS WHEREOF, the undersigned has cause this Guaranty to be
duly executed and delivered as of the date first set forth above.

                              GUARANTOR:

                              AMB PROPERTY, L.P.,
                              a Delaware limited partnership

                              By:   AMB Property Corporation, a Maryland
                                    corporation and its sole general partner


                                    By:  /s/ Gayle P. Starr
                                         ________________________
                                          Name:  Gayle P. Starr
                                          Title: SVP

ACCEPTED:

JPMORGAN CHASE BANK,
 as Administrative Agent

By:   /s/ Christina Gould
      ______________________
      Name:  Christina Gould
      Title: Vice President


J.P. MORGAN EUROPE LIMITED,
 as Administrative Agent

By:   /s/ C. Walsh                 /s/ N. Hall
      _____________________        _____________________
      Name: C. Walsh               Name: N. Hall
      Title: Associate             Title: Associate
<PAGE>
                          ACKNOWLEDGMENT FOR GUARANTOR

STATE OF CALIFORNIA      )
                         ) SS.
COUNTY OF SAN FRANCISCO  )


            On December 6, 2002, before me personally came Gayle P. Starr, to
me known to be the person who executed the foregoing instrument, and who, being
duly sworn by me, did depose and say that [s]he is Senior Vice President of AMB
Property Corporation, and that [s]he executed the foregoing instrument in the
organization's name, and that [s]he had authority to sign the same, and [s]he
acknowledged to me that [s]he executed the same as the act and deed of said
organization for the uses and purposes therein mentioned.

[Seal]
                                    /s/ Jocelyn Clarin Richards
                                    _______________________________
                                    Notary Public