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                            CERTIFICATE OF FORMATION

                                       OF

                                    ARHC, LLC
                       (Pursuant to Section 18-201 of the
                     Delaware Limited Liability Company Act)

         The undersigned, an authorized natural person, for the purpose of
forming a limited liability company, under the provisions and subject to the
requirements of the State of Delaware (particularly Chapter 18, Title 6 of the
Delaware Code and the acts amendatory thereof and supplemental thereto, and
known, identified, and referred to as the "Delaware Limited Liability Company
Act"), hereby certifies that:

         FIRST: The name of the limited liability company (hereinafter called
the "Limited Liability Company") is ARHC, LLC.

         SECOND: The address of the registered office and the name and the
address of the registered agent of the Limited Liability Company required to be
maintained by Section 18-104 of the Delaware Limited Liability Company Act are
1209 Orange Street, City of Wilmington, County of New Castle, State of Delaware;
and its registered agent at such address is The Corporation Trust Company.

         IN WITNESS WHEREOF, this Certificate has been signed on this 22nd day
of February, 1999.

                                                       /s/ Colleen A. Keating
                                                           -------------------
                                                           Colleen Keating
                                                           Authorized Person




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