Exhibit 4
JOINT FILING AGREEMENT
This will confirm the agreement by and between the undersigned that
Amendment No. 2 to the Schedule 13D filed on July 22, 2005 (the "Amendment")
and the Form 3, each filed on or about this date, including any future
amendments thereto, relating to the offer by Spirit Acquisition Corporation, a
Delaware corporation and a wholly-owned subsidiary of McKesson Corporation, a
Delaware corporation, to purchase all the outstanding shares of common stock,
par value $0.01 per share, of D & K Healthcare Resources, Inc., a Delaware
corporation, is being or will be, as applicable, filed on behalf of the
undersigned.
Each of the undersigned hereby acknowledges that pursuant to Rule
13d-1(k) promulgated under the Securities Exchange Act of 1934, as amended,
that each person on whose behalf the Statement is filed is responsible for the
timely filing of such statement and any amendments thereto, and for the
completeness and accuracy of the information concerning such person contained
therein; and that such person is not responsible for the completeness or
accuracy of the information concerning the other persons making the filing,
unless such person knows or has reason to believe that such information is
inaccurate.
This Agreement may be executed in one or more counterparts by each of
the undersigned, and each of which, taken together, shall constitute one and
the same instrument.
Date: August 22, 2005
MCKESSON CORPORATION
By: /s/ Xxxx X. Xxxxxxxx
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Name: Xxxx X. Xxxxxxxx
Title: Executive Vice President,
General Counsel and
Secretary
SPIRIT ACQUISITION CORPORATION
By: /s/ Xxxxxxxx X. Xxxxxxxx
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Name: Xxxxxxxx X. Xxxxxxxx
Title: Vice President and Treasurer
