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                                                                    Exhibit 4.18

                        AmeriSource Health Corporation

            5% Convertible Subordinated Notes due December 1, 2007

                         Registration Rights Agreement
                         -----------------------------

                                                               December 12, 2000

Goldman, Sachs & Co.,
Banc of America Securities LLC
Credit Suisse First Boston Corporation
First Union Securities, Inc.
J.P. Morgan Securities Inc.
c/o Goldman, Sachs & Co.
85 Broad Street
New York, New York 10004

Ladies and Gentlemen:

     AmeriSource Health Corporation, a Delaware corporation (the "Company") and
AmeriSource Corporation (the "Subsidiary Guarantor" and, together with the
Company, the "Issuers"), jointly and severally, propose to issue and sell to the
Purchasers (as defined herein) upon the terms set forth in the Purchase
Agreement (as defined herein) the Company's 5% Convertible Subordinated Notes
due December 1, 2007 (the "Securities"), which are unconditionally guaranteed by
the Subsidiary Guarantor. As an inducement to the Purchasers to enter into the
Purchase Agreement and in satisfaction of a condition to the obligations of the
Purchasers thereunder, the Issuers jointly and severally agree with the
Purchasers for the benefit of Holders (as defined herein) from time to time of
the Registrable Securities (as defined herein) as follows:

     1.  Definitions.
         -----------

     (a)  Capitalized terms used herein without definition shall have the
meanings ascribed to them in the Purchase Agreement.  As used in this Agreement,
the following defined terms shall have the following meanings:

     "Act" or "Securities Act" means the United States Securities Act of 1933,
as amended.

     "Affiliate", of any specified person means any other person which, directly
or indirectly, is in control of, is controlled by, or is under common control
with such specified person.  For purposes of this definition, control of a
person means the power, direct or indirect, to direct or cause the direction of
the management and policies of such person whether by contract or otherwise; and
the terms "controlling" and "controlled" have meanings correlative to the
foregoing.
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     "Closing Date" means the First Time of Delivery as defined in the Purchase
Agreement.

     "Commission" means the United States Securities and Exchange Commission, or
any other federal agency at the time administering the Exchange Act or the
Securities Act, whichever is the relevant statute for the particular purpose.

     "Common Stock" means the Company's Class A Common Stock, par value $0.01
per share.

     "DTC" means The Depository Trust Company.

     "Effective Failure" has the meaning assigned thereto in Section 7(b)
hereof.

     "Effectiveness Period" has the meaning assigned thereto in Section 2(b)(i)
hereof.

     "Effective Time" means the date on which the Commission declares the Shelf
Registration Statement effective or on which the Shelf Registration Statement
otherwise becomes effective.

     "Electing Holder" has the meaning assigned thereto in Section 3(a)(iii)
hereof.

     "Exchange Act" means the United States Securities Exchange Act of 1934, as
amended.

     "Holder" means, any person that is the record owner of Registrable
Securities (and includes any person that has a beneficial interest in any
Registrable Security in book-entry form).

     "Indemnified Person" has the meaning assigned thereto in Section 5(a)
hereto.

     "Indenture" means the Indenture, dated as of December 12, 2000, among the
Company, the Subsidiary Guarantor and Bank One Trust Company, N.A., as amended
and supplemented from time to time in accordance with its terms.

     "Managing Underwriters" means the investment banker or investment bankers
and manager or managers that shall administer an underwritten offering, if any,
conducted pursuant to Section 6 hereof.

     "NASD Rules" means the Rules of the National Association of Securities
Dealers, Inc., as amended from time to time.

     "Notice and Questionnaire" means a Notice of Registration Statement and
Selling Securityholder Questionnaire substantially in the form of Exhibit A
hereto.

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     The term "person" means an individual, partnership, corporation, trust or
unincorporated organization, or a government or agency or political subdivision
thereof.

     "Prospectus" means the prospectus (including, without limitation, any
preliminary prospectus, any final prospectus and any prospectus that discloses
information previously omitted from a prospectus filed as part of an effective
registration statement in reliance upon Rule 430A under the Act) included in the
Shelf Registration Statement, as amended or supplemented by any prospectus
supplement with respect to the terms of the offering of any portion of the
Registrable Securities covered by the Shelf Registration Statement and by all
other amendments and supplements to such prospectus, including all material
incorporated by reference in such prospectus and all documents filed after the
date of such prospectus by the Issuers under the Exchange Act and incorporated
by reference therein.

     "Purchase Agreement" means the purchase agreement, dated as of December 6,
2000, among the Purchasers, the Subsidiary Guarantor and the Company relating to
the Securities.

     "Purchasers" means the Purchasers named in Schedule I to the Purchase
Agreement.

     "Registration Default" has the meaning assigned thereto in Section 7(a)
hereto.

     "Registrable Securities" means all or any portion of the Securities issued
from time to time under the Indenture in registered form and the shares of
Common Stock issuable upon conversion of such Securities; provided, however,
that a security ceases to be a Registrable Security when it is no longer a
Restricted Security.

     "Restricted Security" means any Security or share of Common Stock issuable
upon conversion thereof except any such Security or share of Common Stock which
(i) has been effectively registered under the Securities Act and sold in a
manner contemplated by the Shelf Registration Statement, (ii) has been
transferred in compliance with Rule 144 under the Securities Act (or any
successor provision thereto) or is transferable pursuant to paragraph (k) of
such Rule 144 (or any successor provision thereto) or (iii) has otherwise been
transferred and a new Security or share of Common Stock not subject to transfer
restrictions under the Securities Act has been delivered by or on behalf of the
Issuers in accordance with Section 3.3 of the Indenture.

     "Rules and Regulations" means the published rules and regulations of the
Commission promulgated under the Securities Act or the Exchange Act, as in
effect at any relevant time.

     "Shelf Registration" means a registration effected pursuant to Section 2
hereof.

     "Shelf Registration Statement" means a "shelf" registration statement filed
under the Securities Act providing for the registration of, and the sale on a
continuous or delayed basis by the Holders of, all of the Registrable Securities
pursuant to Rule 415 under the Securities

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Act and/or any similar rule that may be adopted by the Commission, filed by the
Issuers pursuant to the provisions of Section 2 of this Agreement, including the
Prospectus contained therein, any amendments and supplements to such
registration statement, including posteffective amendments, and all exhibits and
all material incorporated by reference in such registration statement.

     "Trust Indenture Act" means the Trust Indenture Act of 1939, or any
successor thereto, and the rules, regulations and forms promulgated thereunder,
as the same shall be amended from time to time.

     The term "underwriter" means any underwriter of Registrable Securities in
connection with an offering thereof under a Shelf Registration Statement.

     (b)  Wherever there is a reference in this Agreement to a percentage of the
"principal amount" of Registrable Securities or to a percentage of Registrable
Securities, any Common Stock constituting Registrable Securities shall be
treated as representing the principal amount of Securities which was surrendered
for conversion or exchange in order to receive such number of shares of Common
Stock.

     2.  Shelf Registration.
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     (a)  The Issuers shall, no later than 90 calendar days following the
Closing Date, file with the Commission a Shelf Registration Statement relating
to the offer and sale of the Registrable Securities by the Holders from time to
time in accordance with the methods of distribution elected by such Holders and
set forth in such Shelf Registration Statement and, thereafter, shall use its
reasonable efforts to cause such Shelf Registration Statement to be declared
effective under the Act no later than 180 calendar days following the Closing
Date; provided, however, that the Issuers may, upon written notice to all
Holders, postpone filing the Shelf Registration Statement or having the Shelf
Registration Statement declared effective, in each case, for a reasonable period
not to exceed 90 days if the Issuers possess material nonpublic information, the
disclosure of which would, in the Company's reasonable judgment, have a material
adverse effect on the Company and its subsidiaries taken as a whole; provided,
further, however, that no Holder shall be entitled to be named as a selling
securityholder in the Shelf Registration Statement or to use the Prospectus
forming a part thereof for resales of Registrable Securities unless such Holder
is an Electing Holder.

     (b)  The Issuers shall use its best efforts:

             (i) To keep the Shelf Registration Statement continuously effective
     in order to permit the Prospectus forming part thereof to be usable by
     Electing Holders, subject to Section 3(d)(v), until the earliest of (1) the
     sale of all Registrable Securities registered under the Shelf Registration
     Statement; (2) the expiration of the period referred to in Rule 144(k) of
     the Act with respect to all Registrable Securities held by Electing

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     Holders that are not Affiliates of the Issuers; and (3) two years from the
     date (the "Effective Date") the Securities are issued (such period being
     referred to herein as the "Effectiveness Period");

             (ii)  After the Effective Time of the Shelf Registration Statement,
     promptly upon the request of any Holder of Registrable Securities that is
     not then an Electing Holder, to take any action reasonably necessary to
     enable such Holder to use the Prospectus forming a part thereof for resales
     of Registrable Securities, including, without limitation, any action
     necessary to identify such Holder as a selling securityholder in the Shelf
     Registration Statement; provided, however, that nothing in this
     subparagraph shall relieve such Holder of the obligation to return a
     completed and signed Notice and Questionnaire to the Company in accordance
     with Section 3(a)(ii) hereof; and

             (iii) If at any time the securities, pursuant to Article XII of the
     Indenture, are convertible into securities other than Common Stock, the
     Company shall, or shall cause any successor under the Indenture to, cause
     such securities to be included in the Shelf Registration Statement no later
     than the date on which the Securities may then be convertible into such
     securities.

Subject to the requirement of applicable laws and the provisions of Section 3(j)
below, the Issuers shall be deemed not to have used their reasonable efforts to
keep the Shelf Registration Statement effective during the requisite period if
the Company or the Subsidiary Guarantor voluntarily takes any action that would
result in Holders of Registrable Securities covered thereby not being able to
offer and sell any of such Registrable Securities during that period.

     (c)  The Issuers may suspend the use of the Prospectus for a period not to
exceed 45 days in any 90-day period or an aggregate of 90 days in any 12-month
period if the Board of Directors of the Company shall have determined in good
faith that because of valid business reasons (not including avoidance of the
Issuer's obligations hereunder), including the acquisition or divestiture of
assets, pending corporate developments and similar events, it is in the best
interests of the Company to suspend such use, and prior to suspending such use
the Issuers provide the Holders with written notice of such suspension, which
notice need not specify the nature of the event giving rise to such suspension.

     3.  Registration Procedures.  In connection with the Shelf Registration
         -----------------------
Statement, the following provisions shall apply:

     (a)  (i) Not less than 30 calendar days prior to the time the Issuers
intend in good faith to cause the Shelf Registration Statement to be declared
effective, the Company shall mail the Notice and Questionnaire to the Holders of
Registrable Securities.  No Holder shall be entitled to be named as a selling
securityholder in the Shelf Registration Statement as of the Effective Time, and
no Holder shall be entitled to use the Prospectus forming a part thereof for
resales of Registrable Securities at any time, unless such Holder has returned a
completed and signed

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Notice and Questionnaire to the Company by the deadline for response set forth
therein; provided, however, Holders of Registrable Securities shall have at
least 28 calendar days from the date on which the Notice and Questionnaire is
first mailed to such Holders to return a completed and signed Notice and
Questionnaire to the Company.

             (ii)  After the Effective Time of the Shelf Registration Statement,
     the Company shall, upon the request of any Holder of Registrable Securities
     that is not then an Electing Holder, promptly send a Notice and
     Questionnaire to such Holder. The Company shall not be required to take any
     action to name such Holder as a selling securityholder in the Shelf
     Registration Statement or to enable such Holder to use the Prospectus
     forming a part thereof for resales of Registrable Securities until such
     Holder has returned a completed and signed Notice and Questionnaire to the
     Company.

             (iii) The term "Electing Holder" shall mean any Holder of
     Registrable Securities that has returned a completed and signed Notice and
     Questionnaire to the Company in accordance with Section 3(a)(i) or 3(a)(ii)
     hereof.

     (b)  The Issuers shall furnish to each Electing Holder, prior to the
Effective Time, a copy of the Shelf Registration Statement initially filed with
the Commission, and shall furnish to such Holders, prior to the filing thereof
with the Commission, copies of each amendment thereto and each amendment or
supplement, if any, to the Prospectus included therein, and shall use their
reasonable efforts to reflect in each such document, at the Effective Time or
when so filed with the Commission, as the case may be, such comments as such
Holders and their respective counsel reasonably may propose.

     (c)  The Issuers shall promptly take such action as may be necessary so
that (i) each of the Shelf Registration Statement and any amendment thereto and
the Prospectus forming part thereof and any amendment or supplement thereto (and
each report or other document incorporated therein by reference in each case)
and the respective rules and regulations thereunder, (ii) each of the Shelf
Registration Statement and any amendment thereto does not, when it becomes
effective, contain an untrue statement of a material fact or omit to state a
material fact required to be stated therein or necessary to make the statements
therein not misleading and (iii) each of the Prospectus forming part of the
Shelf Registration Statement, and any amendment or supplement to such
Prospectus, does not during the Effectiveness Period include an untrue statement
of a material fact or omit to state a material fact necessary in order to make
the statements therein, in the light of the circumstances under which they were
made, not misleading; provided, however, the Company is not required to prepare
an amendment or supplement to the Prospectus forming part of the Shelf
Registration pursuant to this Section 3(c)(iii) during any period from time to
time during which the use of the Prospectus may be suspended by the Company for
the reasons set forth in Sections 2(b), 2(c) or 3(d)(v), after giving written
notice of such suspension to the Holders in accordance with Section 3(d)(v).

                                      -6-
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     (d)  The Company shall promptly advise each Electing Holder, and shall
confirm such advice in writing if so requested by any such Holder:

             (i)    when a Shelf Registration Statement and any amendment
     thereto has been filed with the Commission and when a Shelf Registration
     Statement or any post-effective amendment thereto has become effective, in
     each case making a public announcement thereof by release made to Reuters
     Economic Services and Bloomberg Business News or such other newswire
     service acceptable to the Company;

             (ii)   of any request by the Commission for amendments or
     supplements to the Shelf Registration Statement or the Prospectus included
     therein or for additional information;

             (iii)  of the issuance by the Commission of any stop order
     suspending the effectiveness of the Shelf Registration Statement or the
     initiation of any proceedings for such purpose;

             (iv)   of the receipt by the Issuers of any notification with
     respect to the suspension of the qualification of the securities included
     in the Shelf Registration Statement for sale in any jurisdiction or the
     initiation of any proceeding for such purpose; and

             (v)    of the happening of any event or the existence of any state
     of facts that requires the making of any changes in the Shelf Registration
     Statement or the Prospectus included therein so that, as of such date, such
     Shelf Registration Statement and Prospectus do not contain an untrue
     statement of a material fact and do not omit to state a material fact
     required to be stated therein or necessary to make the statements therein
     (in the case of the Prospectus, in light of the circumstances under which
     they were made) not misleading (which advice shall be accompanied by an
     instruction to such Holders to suspend the use of the Prospectus until the
     requisite changes have been made).

     (e)  The Issuers shall use their best efforts to prevent the issuance, and
if issued to obtain the withdrawal, of any order suspending the effectiveness of
the Shelf Registration Statement at the earliest possible time.

     (f)  The Issuers shall furnish to each Electing Holder, without charge, at
least one copy of the Shelf Registration Statement and all post-effective
amendments thereto, including financial statements and schedules, and, if such
Holder so requests in writing, all reports, other documents and exhibits that
are filed with or incorporated by reference in the Shelf Registration Statement.

                                      -7-
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     (g)  The Issuers shall, during the Effectiveness Period, deliver to each
Electing Holder, without charge, as many copies of the Prospectus (including
each preliminary Prospectus) included in the Shelf Registration Statement and
any amendment or supplement thereto as such Electing Holder may reasonably
request; and the Company consents (except during the continuance of any event
described in Section 3(d)(v) above) to the use of the Prospectus and any
amendment or supplement thereto by each of the Electing Holders in connection
with the offering and sale of the Registrable Securities covered by the
Prospectus and any amendment or supplement thereto during the Effectiveness
Period.

     (h)  Prior to any offering of Registrable Securities pursuant to the Shelf
Registration Statement, the Issuers shall (i) register or qualify or cooperate
with the Electing Holders and their respective counsel in connection with the
registration or qualification of such Registrable Securities for offer and sale
under the securities or "blue sky" laws of such jurisdictions within the United
States as any Electing Holder may reasonably request, (ii) keep such
registrations or qualifications in effect and comply with such laws so as to
permit the continuance of offers and sales in such jurisdictions for so long as
may be necessary to enable any Electing Holder or underwriter, if any, to
complete its distribution of Registrable Securities pursuant to the Shelf
Registration Statement, and (iii) take any and all other actions necessary or
advisable to enable the disposition in such jurisdictions of such Registrable
Securities; provided, however, that in no event shall the Company be obligated
to (A) qualify as a foreign corporation or as a dealer in securities in any
jurisdiction where it would not otherwise be required to so qualify but for this
Section 3(h), (B) file any general consent to service of process in any
jurisdiction where it is not as of the date hereof so subject or (C) subject
itself to taxation in any jurisdiction where it is not as of the date hereof so
subject.

     (i)  Unless any Registrable Securities shall be in book-entry only form,
the Issuers shall cooperate with the Electing Holders to facilitate the timely
preparation and delivery of certificates representing Registrable Securities to
be sold pursuant to the Shelf Registration Statement, which certificates, if so
required by any securities exchange upon which any Registrable Securities are
listed, shall be penned, lithographed or engraved, or produced by any
combination of such methods, on steel engraved borders, and which certificates
shall be free of any restrictive legends and in such permitted denominations and
registered in such names as Electing Holders may request in connection with the
sale of Registrable Securities pursuant to the Shelf Registration Statement.

     (j)  Upon the occurrence of any fact or event contemplated by paragraph
3(d)(v) above, the Issuers shall promptly prepare a post-effective amendment to
any Shelf Registration Statement or an amendment or supplement to the related
Prospectus or file any other required document so that, as thereafter delivered
to purchasers of the Registrable Securities included therein, the Prospectus
will not include an untrue statement of a material fact or omit to state any
material fact necessary to make the statements therein, in the light of the
circumstances under which they were made, not misleading; provided, however, if
the Company determines based upon the advice of counsel that it is advisable to
disclose in the Shelf Registration

                                      -8-
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Statement a financing, acquisition or other corporate transaction or other
material event affecting the Company or its securities, and the Board of
Directors of the Company shall have determined in good faith that such
disclosure would not be in the best interests of the Company and its
stockholders, the Company shall not be required to prepare and file such
amendment, supplement or document for such period as the Board of Directors of
the Company shall have determined in good faith is in the best interests of the
Company. If the Issuers notify the Electing Holders of the occurrence of any
event contemplated by paragraph 3(d)(v) above, the Electing Holder shall suspend
the use of the Prospectus until the requisite changes to the Prospectus have
been made.

     (k)  Not later than the Effective Time of the Shelf Registration Statement,
the Issuers shall provide a CUSIP number for the Registrable Securities that are
debt securities.

     (l)  The Issuers shall use their best efforts to comply with all applicable
Rules and Regulations, and to make generally available to its securityholders as
soon as practicable, but in any event not later than eighteen months after (i)
the effective date (as defined in Rule 158(c) under the Securities Act) of the
Shelf Registration Statement, (ii) the effective date of each post-effective
amendment to the Shelf Registration Statement, and (iii) the date of each filing
by the Company with the Commission of an Annual Report on Form 10-K that is
incorporated by reference in the Shelf Registration Statement, an earnings
statement of the Company and its subsidiaries complying with Section 11(a) of
the Securities Act and the rules and regulations of the Commission thereunder
(including, at the option of the Company, Rule 158).

     (m)  Not later than the Effective Time of the Shelf Registration Statement,
the Issuers shall cause the Indenture to be qualified under the Trust Indenture
Act; in connection with such qualification, the Issuers shall cooperate with the
Trustee under the Indenture and the Holders (as defined in the Indenture) to
effect such changes to the Indenture as may be required for such Indenture to be
so qualified in accordance with the terms of the Trust Indenture Act; and the
Issuers shall execute, and shall use all reasonable efforts to cause the Trustee
to execute, all documents that may be required to effect such changes and all
other forms and documents required to be filed with the Commission to enable
such Indenture to be so qualified in a timely manner.  In the event that any
such amendment or modification referred to in this Section 3(m) involves the
appointment of a new trustee under the Indenture, the Issuers shall appoint a
new trustee thereunder pursuant to the applicable provisions of the Indenture.

     (n)  In the event of an underwritten offering conducted pursuant to Section
6 hereof, the Issuers shall, if requested, promptly include or incorporate in a
Prospectus supplement or post-effective amendment to the Shelf Registration
Statement such information as the Managing Underwriters reasonably agree should
be included therein and to which the Issuers do not reasonably object and shall
make all required filings of such Prospectus supplement or post-effective
amendment as soon as practicable after it is notified of the matters to be
included or incorporated in such Prospectus supplement or post-effective
amendment.

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     (o)  The Issuers shall enter into such customary agreements (including an
underwriting agreement in customary form in the event of an underwritten
offering conducted pursuant to Section 6 hereof) and take all other appropriate
action in order to expedite and facilitate the registration and disposition of
the Registrable Securities, and in connection therewith, if an underwriting
agreement is entered into, cause the same to contain indemnification provisions
and procedures substantially identical to those set forth in Section 5 hereof
with respect to all parties to be indemnified pursuant to Section 5 hereof.

     (p)  The Issuers shall:

             (i)  upon request by the Electing Holder (A) make reasonably
     available for inspection by Electing Holders, any underwriter participating
     in any disposition pursuant to the Shelf Registration Statement, and any
     attorney, accountant or other agent retained by such Holders or any such
     underwriter all relevant financial and other records, pertinent corporate
     documents and properties of the Company and its subsidiaries, and (B) cause
     the Company's officers, directors and employees to supply all information
     reasonably requested by such Holders or any such underwriter, attorney,
     accountant or agent in connection with the Shelf Registration Statement, in
     each case, as is customary for similar due diligence examinations;
     provided, however, that all records, information and documents that are
     designated in writing by the Issuers, in good faith, as confidential shall
     be kept confidential by such Holders and any such underwriter, attorney,
     accountant or agent, unless such disclosure is made in connection with a
     court proceeding or required by law, or such records, information or
     documents become available to the public generally or through a third party
     without an accompanying obligation of confidentiality; and provided further
     that, if the foregoing inspection and information gathering would otherwise
     disrupt the Company's conduct of its business, such inspection and
     information gathering shall, to the greatest extent possible, be
     coordinated on behalf of the Electing Holders and the other parties
     entitled thereto by one counsel designated by and on behalf of Electing
     Holders and other parties reasonably acceptable to the Company; in the
     event that any Holder, underwriter, attorney, accountant or agent is
     required to disclose confidential information of the Company by law or in a
     court proceeding, such Holder, underwriter, attorney, accountant or agent
     will provide the Company with notice of such disclosure requirement and
     copies of the information to be disclosed, if possible, and will cooperate
     with the Company, to the extent reasonably practicable, to limit such
     disclosure;

             (ii) in connection with any underwritten offering conducted
     pursuant to Section 6 hereof, make such representations and warranties to
     the Holders participating in such underwritten offering and to the Managing
     Underwriters, in form, substance and scope as are customarily made by the
     Issuers to underwriters in primary underwritten offerings of equity and
     convertible debt securities and covering matters including, but not limited
     to, those set forth in the Purchase Agreement;

                                      -10-
<PAGE>

             (iii)  in connection with any underwritten offering conducted
     pursuant to Section 6 hereof, obtain opinions of counsel to the Issuers
     (which counsel and opinions (in form, scope and substance) shall be
     reasonably satisfactory to the Managing Underwriters) addressed to the
     underwriters, covering such matters as are customarily covered in opinions
     requested in primary underwritten offerings of equity and convertible debt
     securities and such other matters as may be reasonably requested by such
     Holders and underwriters (it being agreed that the matters to be covered by
     such opinions shall include, without limitation, as of the date of the
     opinion and as of the Effective Time of the Shelf Registration Statement or
     most recent post-effective amendment thereto, as the case may be, the
     absence from the Shelf Registration Statement and the Prospectus, including
     the documents incorporated by reference therein, of an untrue statement of
     a material fact or the omission of a material fact required to be stated
     therein or necessary to make the statements therein not misleading);

             (iv)   in connection with any underwritten offering conducted
     pursuant to Section 6 hereof, obtain "cold comfort" letters and updates
     thereof from the independent public accountants of the Company (and, if
     necessary, from the independent public accountants of any subsidiary of the
     Company or of any business acquired by the Company for which financial
     statements and financial data are, or are required to be, included in the
     Shelf Registration Statement), addressed to each Holder participating in
     such underwritten offering (if such Holder has provided such letter,
     representations or documentation, if any, required for such cold comfort
     letter to be so addressed) and the underwriters, in customary form and
     covering matters of the type customarily covered in "cold comfort" letters
     in connection with primary underwritten offerings;

             (v)    in connection with any underwritten offering conducted
     pursuant to Section 6 hereof, deliver such documents and certificates as
     may be reasonably requested by any Holders participating in such
     underwritten offering and the Managing Underwriters, if any, including,
     without limitation, certificates to evidence compliance with Section 3(j)
     hereof and with any conditions contained in the underwriting agreement or
     other agreements entered into by the Company.

     (q)  The Company will use its reasonable efforts to cause the Common Stock
issuable upon conversion of the Securities to be listed on the New York Stock
Exchange or other stock exchange or trading system on which the Common Stock
primarily trades on or prior to the Effective Time of the Shelf Registration
Statement hereunder.

     (r)  In the event that any broker-dealer registered under the Exchange Act
shall be an "affiliate", (as defined in Rule 2720(b)(1) of the NASD Rules (or
any successor provision thereto)) of the Company or has a "conflict of interest"
(as defined in Rule 2720(b)(7) of the NASD Rules (or any successor provision
thereto)) and such broker-dealer shall underwrite, participate as a member of an
underwriting syndicate or selling group or assist in the distribution of any
Registrable Securities covered by the Shelf Registration Statement, whether as a

                                      -11-
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Holder of such Registrable Securities or as an underwriter, a placement or sales
agent or a broker or dealer in respect thereof, or otherwise, the Company shall
assist such broker-dealer in complying with the requirements of the NASD Rules,
including, without limitation, by (A) engaging a "qualified independent
underwriter" (as defined in Rule 2720(b)(15) of the NASD Rules (or any successor
provision thereto)) to participate in the preparation of the registration
statement relating to such Registrable Securities, to exercise usual standards
of due diligence in respect thereto and to recommend the public offering price
of such Registrable Securities, (B) indemnifying such qualified independent
underwriter to the extent of the indemnification of underwriters provided in
Section 5 hereof, and (C) providing such information to such broker-dealer as
may be required in order for such broker-dealer to comply with the requirements
of the NASD Rules.

     (s)  The Issuers shall use their best efforts to take all other steps
necessary to effect the registration, offering and sale of the Registrable
Securities covered by the Shelf Registration Statement contemplated hereby.

     4.   Registration Expenses.  Except as otherwise provided in Section 3, the
          ---------------------
Company shall bear all fees and expenses incurred in connection with the
performance of its obligations under Sections 2 and 3 hereof and shall bear or
reimburse the Electing Holders for the reasonable fees and disbursements of a
single counsel selected by a plurality of all Electing Holders who own an
aggregate of not less than 25% of the Registrable Securities covered by the
Shelf Registration Statement to act as counsel therefore in connection therewith
(which counsel shall be reasonably satisfactory to the Company).  Each Electing
Holder shall pay all underwriting discounts and commissions and transfer taxes,
if any, relating to the sale or disposition of such Electing Holder's
Registrable Securities pursuant to the Shelf Registration Statement.

     5.   Indemnification and Contribution.
          --------------------------------

     (a)  Indemnification by the Issuers.  Upon the registration of the
          ------------------------------
Registrable Securities pursuant to Section 2 hereof, the Issuers, jointly and
severally, shall indemnify and hold harmless each Electing Holder and each
underwriter, selling agent or other securities professional that may be deemed
an underwriter within the meaning of Section 2(11) of the Securities Act, if
any, which facilitates the disposition of Registrable Securities, and each of
their respective officers and directors and each person who controls such
Electing Holder, underwriter, selling agent or other securities professional
within the meaning of Section 15 of the Securities Act or Section 20 of the
Exchange Act (each such person being sometimes referred to as an "Indemnified
Person") against any losses, claims, damages or liabilities, joint or several,
to which such Indemnified Person may become subject under the Securities Act or
otherwise, insofar as such losses, claims, damages or liabilities (or actions in
respect thereof) arise out of or are based upon an untrue statement or alleged
untrue statement of a material fact contained in any Shelf Registration
Statement under which such Registrable Securities are to be registered under the
Securities Act, or any Prospectus contained therein or furnished by the Issuers
to any Indemni-

                                      -12-
<PAGE>

fied Person, or any amendment or supplement thereto, or arise out of or are
based upon the omission or alleged omission to state therein a material fact
required to be stated therein or necessary to make the statements therein not
misleading, and the Issuers, jointly and severally, hereby agree to reimburse
such Indemnified Person for any legal or other expenses reasonably incurred by
them in connection with investigating or defending any such action or claim as
such expenses are incurred; provided, however, that the Issuers shall not be
liable to any such Indemnified Person in any such case to the extent that any
such loss, claim, damage or liability arises out of or is based upon an untrue
statement or alleged untrue statement or omission or alleged omission made in
such Shelf Registration Statement or Prospectus, or amendment or supplement, in
reliance upon and in conformity with written information furnished to the
Issuers by such Indemnified Person expressly for use therein; provided, further,
in a disposition of Registrable Securities that does not involve (in whole or in
part) an underwritten offering conducted pursuant to Section 6 hereof, the
Company shall not be liable to any Electing Holder or any officer and director
and each person who controls such Electing Holder (an "Indemnified Electing
Holder") pursuant to the foregoing to the extent that any such loss, claim,
damage or liability of such Indemnified Electing Holder results from the fact
that such Indemnified Electing Holder sold Registrable Securities to a person as
to whom it shall be established by conclusive evidence that there was not sent
or given, at or prior to the written confirmation of such a sale, a copy of the
Prospectus (excluding documents incorporated by reference) or the Prospectus as
then amended or supplemented (excluding documents incorporated by reference) in
any case where such delivery is required by the Act, if the Company has
previously furnished copies thereof upon request therefor in sufficient quantity
to such Indemnified Electing Holder and the loss, claim, damage or liability of
such Indemnified Electing Holder results from an untrue statement or omission of
a material fact contained in the preliminary prospectus which was identified in
writing at such time to such Indemnified Electing Holder and corrected in the
Prospectus (excluding any document incorporated by reference) or in the
Prospectus as then amended or supplemented (excluding documents incorporated by
reference) and such correction would have cured the defect giving rise to such
loss, claim, damage or liability.

     (b)  Indemnification by the Holders and any Agents and Underwriters.  Each
          --------------------------------------------------------------
Electing Holder agrees, as a consequence of the inclusion of any of such
Holder's Registrable Securities in such Shelf Registration Statement, and each
underwriter, selling agent or other securities professional, if any, which
facilitates the disposition of Registrable Securities shall agree, as a
consequence of facilitating such disposition of Registrable Securities,
severally and not jointly, to (i) indemnify and hold harmless the Issuers, their
directors, officers who sign any Shelf Registration Statement and each person,
if any, who controls the Company within the meaning of either Section 15 of the
Securities Act or Section 20 of the Exchange Act, against any losses, claims,
damages or liabilities to which the Company or such other persons may become
subject, under the Securities Act or otherwise, insofar as such losses, claims,
damages or liabilities (or actions in respect thereof) arise out of or are based
upon an untrue statement or alleged untrue statement of a material fact
contained in such Shelf Registration Statement or Prospectus, or any amendment
or supplement, or arise out of or are based upon the omission

                                      -13-
<PAGE>

or alleged omission to state therein a material fact required to be stated
therein or necessary to make the statements therein not misleading, in each case
to the extent, but only to the extent, that such untrue statement or alleged
untrue statement or omission or alleged omission was made in reliance upon and
in conformity with written information furnished to the Company by such Holder,
underwriter, selling agent or other securities professional expressly for use
therein, and (ii) reimburse the Issuers for any legal or other expenses
reasonably incurred by the Company in connection with investigating or defending
any such action or claim as such expenses are incurred.

     (c)  Notices of Claims, Etc.  Promptly after receipt by an indemnified
          ----------------------
party under subsection (a) or (b) above of notice of the commencement of any
action, such indemnified party shall, if a claim in respect thereof is to be
made against an indemnifying party under this Section 5, notify such
indemnifying party in writing of the commencement thereof; but the omission so
to notify the indemnifying party shall not relieve it from any liability which
it may have to any indemnified party otherwise than under this Section 5. In
case any such action shall be brought against any indemnified party and it shall
notify an indemnifying party of the commencement thereof, such indemnifying
party shall be entitled to participate therein and, to the extent that it shall
wish, jointly with any other indemnifying party similarly notified, to assume
the defense thereof, with counsel reasonably satisfactory to such indemnified
party (who shall not, except with the consent of the indemnified party, be
counsel to the indemnifying party), and, after notice from the indemnifying
party to such indemnified party of its election so to assume the defense
thereof, such indemnifying party shall not be liable to such indemnified party
under this Section 5 for any legal expenses of other counsel or any other
expenses, in each case subsequently incurred by such indemnified party, in
connection with the defense thereof other than reasonable costs of
investigation.  No indemnifying party shall, without the written consent of the
indemnified party, effect the settlement or compromise of, or consent to the
entry of any judgment with respect to, any pending or threatened action or claim
in respect of which indemnification or contribution may be sought hereunder
(whether or not the indemnified party is an actual or potential party to such
action or claim) unless such settlement, compromise or judgment (i) includes an
unconditional release of the indemnified party from all liability arising out of
such action or claim and (ii) does not include a statement as to, or an
admission of, fault, culpability or a failure to act, by or on behalf of any
indemnified party.  No indemnifying party shall be required to indemnify an
indemnified party for any amount paid or payable in the settlement of any
action, proceeding or investigation without the prior written consent of such
indemnifying party, which consent shall not be unreasonably withheld.

     (d)  Contribution.  If the indemnification provided for in this Section 5
          ------------
is unavailable to or insufficient to hold harmless an indemnified party under
subsection (a) or (b) above in respect of any losses, claims, damages or
liabilities (or actions in respect thereof) referred to therein, then each
indemnifying party shall contribute to the amount paid or payable by such
indemnified party as a result of such losses, claims, damages or liabilities (or
actions in respect thereof) in such proportion as is appropriate to reflect the
relative fault of the indemnifying

                                      -14-
<PAGE>

party and the indemnified party in connection with the statements or omissions
which resulted in such losses, claims, damages or liabilities (or actions in
respect thereof), as well as any other relevant equitable considerations. The
relative fault of such indemnifying party and indemnified party shall be
determined by reference to, among other things, whether the untrue or alleged
untrue statement of a material fact or omission or alleged omission to state a
material fact relates to information supplied by such indemnifying party or by
such indemnified party, and the parties, relative intent, knowledge, access to
information and opportunity to correct or prevent such statement or omission.
The parties hereto agree that it would not be just and equitable if contribution
pursuant to this Section 5(d) were determined by pro rata allocation (even if
the Electing Holders or any underwriters, selling securities professionals or
all of them were treated as one purpose) or by any other method of allocation
which does not the equitable considerations referred to in this Section 5(d).
The amount paid or payable by an indemnified party as a result of the losses, or
liabilities (or actions in respect thereof) referred to above to include any
legal or other fees or expenses reasonably incurred by such indemnified party in
connection with investigating or defending any such action or claim. No person
guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of
the Securities Act) shall be entitled to contribution from any person who was
not guilty of such fraudulent misrepresentation. The obligations of the Electing
Holders and any underwriters, selling agents or other securities professionals
in this Section 5(d) to contribute shall be several in proportion to the
percentage of principal amount of Registrable Securities registered or
underwritten, as the case may be, by them and not joint.

     (e)  Limitation of Liability.  Notwithstanding any other provision of this
          -----------------------
Section 5, in no event will any (i) Electing Holder be required to undertake
liability to any person under this Section 5 for any amounts in excess of the
dollar amount of the proceeds to be received by such Holder from the sale of
such Holder's Registrable Securities (after deducting any fees, discounts and
commissions applicable thereto) pursuant to any Shelf Registration Statement
under which such Registrable Securities are to be registered under the
Securities Act and (ii) underwriter, agents or other entity for such take
account of The amount paid claims, damages shall be deemed selling agent or
other securities professional be required to undertake liability to any person
hereunder for any amounts in excess of the discount, commission or other
compensation payable to such underwriter, selling agent or other securities
professional with respect to the Registrable Securities underwritten by it and
distributed to the public.

     (f)  Remedy not Exclusive.  The obligations of the Issuers under this
          --------------------
Section 5 shall be in addition to any liability which the Issuers may otherwise
have to any Indemnified Person and the obligations of any Indemnified Person
under this Section 5 shall be in addition to any liability which such
Indemnified Person may otherwise have to the Issuers.  The remedies provided in
this Section 5 are not exclusive and shall not limit any rights or remedies
which may otherwise be available to an indemnified party at law or in equity.

     6.  Underwritten Offering.  Any Holder of Registrable Securities who
         ---------------------
desires to do so may sell Registrable Securities (in whole or in part) in an
underwritten offering; provided

                                      -15-
<PAGE>

that (i) the Electing Holders of at least 33-1/3% in aggregate principal amount
of the Registrable Securities then covered by the Shelf Registration Statement
shall request such an offering and (ii) at least such aggregate principal amount
of such Registrable Securities shall be included in such offering; and provided
further that the Issuers shall not be obligated to cooperate with more than one
underwritten offering during the Effectiveness Period. Upon receipt of such a
request, the Company shall provide all Holders of Registrable Securities written
notice of the request, which notice shall inform such Holders that they have the
opportunity to participate in the offering. In any such underwritten offering,
the investment banker or bankers and manager or managers that will administer
the offering will be selected by, and the underwriting arrangements with respect
thereto (including the size of the offering) will be approved by, the holders of
a majority of the Registrable Securities to be included in such offering;
provided, however, that such investment bankers and managers and underwriting
arrangements must be reasonably satisfactory to the Company. No Holder may
participate in any underwritten offering contemplated hereby unless (a) such
Holder agrees to sell such Holder's Registrable Securities to be included in the
underwritten offering in accordance with any approved underwriting arrangements,
(b) such Holder completes and executes all reasonable questionnaires, powers of
attorney, indemnities, underwriting agreements, lock-up letters and other
documents required under the terms of such approved underwriting arrangements,
and (c) if such Holder is not then an Electing Holder, such Holder returns a
completed and signed Notice and Questionnaire to the Company in accordance with
Section 3(a)(2) hereof within a reasonable amount of time before such
underwritten offering. The Holders participating in any underwritten offering
shall be responsible for any underwriting discounts and commissions and fees
and, subject to Section 4 hereof, expenses of their own counsel. The Company
shall pay all expenses customarily borne by issuers, including but not limited
to filing fees, the fees and disbursements of its counsel and independent public
accountants and any printing expenses incurred in connection with such
underwritten offering. Notwithstanding the foregoing or the provisions of
Section 3(n) hereof, upon receipt of a request from the Managing Underwriter or
a representative of holders of a majority of the Registrable Securities to be
included in an underwritten offering to prepare and file an amendment or
supplement to the Shelf Registration Statement and Prospectus in connection with
an underwritten offering, the Company may delay the filing of any such amendment
or supplement for up to 90 days if the Board of Directors of the Company shall
have determined in good faith that the Company has a bona fide business reason
for such delay.

     7.   Liquidated Damages.
          ------------------

     (a)  Notwithstanding any postponement permitted by Section 2(a) hereof, if
(i) on or prior to the 90th day following the Closing Date, a Shelf Registration
Statement has not been filed with the Commission or (ii) on or prior to the
180th day following the Closing Date, such Shelf Registration Statement is not
declared effective by the Commission (each, a "Registration Default"), the
Issuers shall be required to pay liquidated damages ("Liquidated Damages"), from
and including the day following such Registration Default until such Shelf
Registration

                                      -16-
<PAGE>

Statement is either so filed or so filed and subsequently declared effective, as
applicable, at a rate per annum equal to an additional one-quarter of one
percent (0.25%) of the principal amount of Registrable Securities, to and
including the 90th day following such Registration Default and one-half of one
percent (O.5%) thereof from and after the 91st day following such Registration
Default.

     (b)  In the event that the Shelf Registration Statement ceases to be
effective (or the Holders of Registrable Securities are otherwise prevented or
restricted by the Issuers from effecting sales pursuant thereto, including,
without limitation, for the reasons set forth in Section 2(b) or Section 3(j),
notwithstanding the fact that such reasons are not deemed a failure by the
Company to keep the Registration Statement effective under Section 2(b)) (an
"Effective Failure") for more than 45 days, whether or not consecutive, in any
90-day period, or more than 90 days, whether or not consecutive, during any 12-
month period, then the Issuers shall pay Liquidated Damages at a rate per annum
equal to an additional one-half of one percent (0.5%) from the 46th day of the
applicable 90-day period or the 91st day of the applicable 12-month period, as
the case may be, that such Shelf Registration Statement ceases to be effective
(or the Holders of Registrable Securities are otherwise prevented or restricted
by the Issuers from effecting sales pursuant thereto) until the earlier of (i)
the time the Shelf Registration Statement again becomes effective or the Holders
of Registrable Securities are again able to make sales under the Shelf
Registration Statement or (2) the time the Effectiveness Period expires.  For
the purpose of determining an Effective Failure, days on which the Issuers have
been obligated to pay Liquidated Damages in accordance with the foregoing in
respect of a prior Effective Failure within the applicable 90-day or 12-month
period, as the case may be, shall not be included.

     (c)  In the event the Issuers fail to file a post-effective amendment to
the Shelf Registration Statement, or the post-effective amendment is not
declared effective, within the periods required by Section 3, the Issuers shall
pay Liquidated Damages at a rate per annum equal to an additional one-half of
one percent (0.5%) from and including the date of such Registration Default
until such time as such Registration Default is cured.

     (d)  Any amounts to be paid as Liquidated Damages pursuant to paragraphs
(a), (b) or (c) of this Section 7 shall be paid semi-annually in arrears, with
the first semi-annual payment due on the first Interest Payment Date (as defined
in the Indenture), as applicable, following the date of such Registration
Default.  Such Liquidated Damages will accrue (1) in respect of the Securities
at the rates set forth in paragraphs (a), (b) or (c) of this Section 7, as
applicable, on the principal amount of the Securities.  If any of the
Registrable Securities shall have been converted into Common Stock, then the
amount of Liquidated Damages payable under this Section 7 per share of Common
Stock so converted shall be determined by dividing (x) the amount that would
have been payable hereunder on the aggregate principal amount so converted by
(y) the number of shares of Common Stock issued upon such conversion.

                                      -17-
<PAGE>

     (e)  The Liquidated Damages as set forth in this Section 7 shall be the
exclusive monetary remedy available to the Holders of Registrable Securities for
such Registration Default or Effective Failure.  In no event shall the Company
be required to pay Liquidated Damages in excess of the applicable maximum amount
of one-half of one percent (0.5%) set forth above, regardless of whether one or
multiple Registration Defaults exist.

     8.   Miscellaneous.
          -------------

     (a)  Other Registration Rights.  The Issuers may grant registration rights
          -------------------------
that would permit any Person that is a third party the right to piggyback on any
Shelf Registration Statement, provided that if the Managing Underwriter of any
underwritten offering conducted pursuant to Section 6 hereof notifies the
Issuers and the Electing Holders that the total amount of securities which the
Electing Holders and the holders of such piggyback rights intend to include in
any Shelf Registration Statement is so large as to materially threaten the
success of such offering (including the price at which such securities can be
sold), then the amount, number or kind of securities to be offered for the
account of holders of such piggyback rights will be reduced to the extent
necessary to reduce the total amount of securities to be included in such
offering to the amount, number and kind recommended by the Managing Underwriter
prior to any reduction in the amount of Registrable Securities to be included in
such Shelf Registration Statement.

     (b)  Specific Performance.  The parties hereto acknowledge that there would
          --------------------
be no adequate remedy at law if the Issuers fail to perform any of their
obligations hereunder and that the Purchasers and the Holders from time to time
may be irreparably harmed by any such failure, and accordingly agree that the
Purchasers and such Holders, in addition to any other remedy to which they may
be entitled at law or in equity and without limiting the remedies available to
the Electing Holders under Section 7 hereof, shall be entitled to compel
specific performance of the obligations of the Issuers under this Registration
Rights Agreement in accordance with the terms and conditions of this
Registration Rights Agreement, in any court of the United States or any State
thereof having jurisdiction.

     (c)  Amendments and Waivers.  This Agreement, including this Section 8(c),
          ----------------------
may be amended, and waivers or consents to departures from the provisions hereof
may be given, only by a written instrument duly executed by the Issuers and the
holders of a majority in aggregate principal amount of Registrable Securities
then outstanding.  Each Holder of Registrable Securities outstanding at the time
of any such amendment, waiver or consent or thereafter shall be bound by any
amendment, waiver or consent effected pursuant to this Section 8(c), whether or
not any notice, writing or marking indicating such amendment, waiver or consent
appears on the Registrable Securities or is delivered to such Holder.

     (d)  Notices.  All notices and other communications provided for or
          -------
permitted hereunder shall be given as provided in the Indenture.

                                      -18-
<PAGE>

     (e)  Parties in Interest.  The parties to this Agreement intend that all
          -------------------
Holders of Registrable Securities shall be entitled to receive the benefits of
this Agreement and that any Electing Holder shall be bound by the terms and
provisions of this Agreement by reason of such election with respect to the
Registrable Securities which are included in a Shelf Registration Statement.
All the terms and provisions of this Agreement shall be binding upon, shall
inure to the benefit of and shall be enforceable by the respective successors
and assigns of the parties hereto and any Holder from time to time of the
Registrable Securities to the aforesaid extent.  In the event that any
transferee of any Holder of Registrable Securities shall acquire Registrable
Securities, in any manner, whether by gift, bequest, purchase, operation of law
or otherwise, such transferee shall, without any further writing or action of
any kind, be entitled to receive the benefits of and, if an Electing Holder, be
conclusively deemed to have agreed to be bound by and to perform all of the
terms and provisions of this Agreement to the aforesaid extent.

     (f)  Counterparts.  This Agreement may be executed in any number of
          ------------
counterparts and by the parties hereto in separate counterparts, each of which
when so executed shall be deemed to be an original and all of which taken
together shall constitute one and the same agreement.

     (g)  Headings.  The headings in this agreement are for convenience of
          --------
reference only and shall not limit or otherwise affect the meaning hereof.

     (h)  Governing Law.  This Agreement shall be governed by and construed in
          -------------
accordance with the laws of the State of New York.

     (i)  Severability.  In the event that any one or more of the provisions
          ------------
contained herein, or the application thereof in any circumstances, is held
invalid, illegal or unenforceable in any respect for any reason, the validity,
legality and enforceability of any such provision in every other respect and of
the remaining provisions hereof shall not be in any way impaired or affected
thereby, it being intended that all of the rights and privileges of the parties
hereto shall be enforceable to the fullest extent permitted by law.

     (j)  Survival.  The respective indemnities, agreements, representations,
          --------
warranties and other provisions set forth in this Agreement or made pursuant
hereto shall remain in full force and effect, regardless of any investigation
(or any statement as to the results thereof) made by or on behalf of any
Electing Holder, any director, officer or partner of such Holder, any agent or
underwriter, any director, officer or partner of such agent or underwriter, or
any controlling person of any of the foregoing, and shall survive the transfer
and registration of the Registrable Securities of such Holder.

                                      -19-
<PAGE>

     Please confirm that the foregoing correctly sets forth the agreement
between the Issuers and you.

                                      Very truly yours,

                                      AmeriSource Health Corporation

                                      By: /s/ W. D. Sprague
                                         ---------------------------------
                                         Name:  William D. Sprague
                                         Title: Vice President

                                      AmeriSource Corporation

                                      By: /s/ W. D. Sprague
                                         ---------------------------------
                                         Name:  William D. Sprague
                                         Title: Vice President



Accepted as of the date hereof:
Goldman, Sachs & Co.
Banc of America Securities LLC
Credit Suisse First Boston Corporation
First Union Securities, Inc.
J.P. Morgan Securities Inc


By: /s/ Goldman, Sachs & Co.
   --------------------------------
        (Goldman, Sachs & Co.)


On behalf of each of the Purchasers

                                      -20-