EXHIBIT (a)(1)(I)


This announcement is neither an offer to purchase nor a solicitation of an offer
 to sell Shares (as defined below). The Offer (as defined below) is made solely
 by the Offer to Purchase, dated May 6, 2004 (the "Offer to Purchase"), and the
 related Letter of Transmittal, and is being made to all holders of Shares. The
 Offer is not being made to (nor will tenders be accepted from or on behalf of)
  holders of Shares in any jurisdiction in which the making of the Offer or the
acceptance thereof would not be in compliance with the laws of such jurisdiction
           or any administrative or judicial action pursuant thereto.

                           NOTICE OF OFFER TO PURCHASE
                     ALL OUTSTANDING SHARES OF COMMON STOCK
                                       OF
                      ONESOURCE INFORMATION SERVICES, INC.
                                       AT
                               $8.85 NET PER SHARE
                                       BY
                             OSIS ACQUISITION CORP.
                       A DIRECT WHOLLY-OWNED SUBSIDIARY OF
                                  INFOUSA INC.

      OSIS Acquisition Corp., a Delaware corporation ("Purchaser") and a direct
wholly-owned subsidiary of infoUSAInc., a Delaware corporation ("infoUSA"), is
offering to purchase all outstanding shares of common stock, par value $0.01 per
share, together with the associated Rights (as defined in the Introduction to
the Offer to Purchase) (the "Shares"), of OneSource Information Services, Inc.,
a Delaware corporation("OneSource"), at a price of $8.85 per Share, net to the
seller in cash, without interest thereon (the "Offer Price"), upon the terms and
subject to the conditions set forth in the Offer to Purchase, dated May 6, 2004,
and in the related Letter of Transmittal (which, together with any amendments or
supplements thereto, constitute the "Offer"). Following consummation of the
Offer, Purchaser intends to effect the Merger (as defined below).

              THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00
            MIDNIGHT, NEW YORK CITY TIME, ON THURSDAY, JUNE 3, 2004,
                         UNLESS THE OFFER IS EXTENDED.

      THE OFFER IS CONDITIONED UPON, AMONG OTHER THINGS, THERE BEING VALIDLY
TENDERED AND NOT PROPERLY WITHDRAWN PRIOR TO THE EXPIRATION OF THE OFFER THAT
NUMBER OF SHARES WHICH CONSTITUTES AT LEAST 51% OF THE OUTSTANDING SHARES OF
ONESOURCE ON A FULLY-DILUTED BASIS. THE OFFER IS ALSO SUBJECT TO THE OTHER
CONDITIONS SET FORTH IN SECTION 14 OF THE OFFER TO PURCHASE.







      The Offer is being made pursuant to an Agreement and Plan of Merger, dated
as of April 29, 2004 (the "Merger Agreement"), by and among infoUSA, Purchaser
and OneSource. The purpose of the Offer is to acquire for cash as many
outstanding Shares as possible as a first step in acquiring control of, and the
entire equity interest in, OneSource. The Merger Agreement provides, among other
things, for the commencement of the Offer by Purchaser and further provides that
after the purchase of Shares pursuant to the Offer, subject to the satisfaction
or waiver of certain conditions, Purchaser will be merged with and into
OneSource (the "Merger"), with OneSource surviving the Merger as a direct,
wholly-owned subsidiary of infoUSA. At the effective time of the Merger, each
outstanding Share (other than Shares held in the treasury of OneSource or its
subsidiaries, Shares owned by infoUSA or Purchaser or any of their affiliates
prior to the effective time of the Merger, and Shares owned by stockholders who
have properly exercised their appraisal rights under Delaware law) will be
converted into the right to receive $8.85 in cash without interest.

      Concurrently with the execution of the Merger Agreement, infoUSA and
Purchaser entered into agreements with certain stockholders of OneSource,
pursuant to which such stockholders have agreed to validly tender (and not to
withdraw) all of their Shares in the Offer, which Shares collectively represent
approximately 34% of OneSource's outstanding Shares.

      The Special Committee of the Board of Directors of OneSource and the Board
of Directors of OneSource have approved and declared advisable the Merger
Agreement and the transactions contemplated thereby, including the Offer and the
Merger, have determined that each of the Offer and the Merger is in the best
interests of OneSource stockholders, and have recommended that OneSource
stockholders accept the Offer and tender all of their Shares pursuant to the
Offer.

      For purposes of the Offer, Purchaser will be deemed to have accepted for
payment, and thereby purchased, Shares validly tendered as, if and when
Purchaser gives oral or written notice to Wells Fargo Bank, N.A. (the
"Depositary") of its acceptance of such Shares for payment pursuant to the
Offer. In all cases upon the terms and subject to the conditions of the Offer,
payment for Shares purchased pursuant to the Offer will be made by deposit of
the purchase price therefor with the Depositary, which will act as agent for
tendering stockholders for the purpose of receiving payment from Purchaser and
transmitting payment to validly tendering stockholders whose Shares have
theretofore been accepted for payment. In all cases, payment for Shares
purchased pursuant to the Offer will be made only after timely receipt by the
Depositary of (i) share certificates for such Shares or a timely Book-Entry
Confirmation (as defined in Section 2 of the Offer to Purchase) with respect to
such Shares and (ii) the Letter of Transmittal, properly completed and duly
executed, with any required signature guarantees, or an Agent's Message(as
defined in Section 2 of the Offer to Purchase) and (iii) any other documents
required by the Letter of Transmittal. Under no circumstances will interest on
the purchase price for Shares be paid, regardless of any extension of the Offer
or any delay in making such payment.

      The term "Expiration Date" means 12:00 midnight, New York City time, on
Thursday, June 3, 2004, unless and until Purchaser extends the period of time
during which the Offer is open, in which event the term "Expiration Date" shall
mean the latest time and date at which the Offer, as so extended by Purchaser,
shall expire. Subject to the terms of the Offer and the Merger








Agreement and the applicable rules and regulations of the Securities and
Exchange Commission, Purchaser expressly reserves the right, in its sole
discretion, at any time or from time to time, to extend the period of time
during which the Offer is open by giving oral or written notice of such
extension to the Depositary. Any such extension will be followed as promptly as
practicable by a public announcement thereof, with any announcement of an
extension to be made no later than 9:00 a.m., New York City time, on the next
business day after the previously scheduled Expiration Date. Except as provided
by applicable law and without limiting the manner in which Purchaser may choose
to make a public announcement, Purchaser shall have no obligation to publish,
advertise or otherwise communicate any such public announcement other than by
issuing a press release. During any extension of the Offer, all Shares
previously tendered and not withdrawn will remain tendered pursuant to the
Offer, subject to the rights of a tendering stockholder to withdraw the tendered
Shares.

      In accordance with the provisions of Rule14d-11 under the Securities
Exchange Act of 1934 (the "Exchange Act"), Purchaser may provide a subsequent
offering period of three business days to twenty business days in length
following the expiration of the Offer on the Expiration Date (the "Subsequent
Offering Period") to solicit more Shares. A Subsequent Offering Period would be
an additional period of time, following the expiration of the Offer and the
purchase of Shares in the Offer, during which stockholders may tender Shares not
previously tendered into the Offer. A Subsequent Offering Period, if one is
included, is not an extension of the Offer, which already will have been
completed. PURCHASER DOES NOT CURRENTLY INTEND TO INCLUDE A SUBSEQUENT OFFERING
PERIOD IN THE OFFER, ALTHOUGH IT RESERVES THE RIGHT TO DO SO IN ITS SOLE
DISCRETION. PURSUANT TO RULE14D-7 UNDER THE EXCHANGE ACT, NO WITHDRAWAL RIGHTS
APPLY TO SHARES TENDERED DURING A SUBSEQUENT OFFERING PERIOD OR WITH RESPECT TO
SHARES TENDERED IN THE OFFER AND ACCEPTED FOR PAYMENT. THE SAME OFFER PRICE WILL
BE PAID TO STOCKHOLDERS TENDERING SHARES IN THE OFFER AND IN A SUBSEQUENT
OFFERING PERIOD, IF ONE IS INCLUDED.

      Except as otherwise provided in the Offer to Purchase, tenders of Shares
made pursuant to the Offer are irrevocable. Shares tendered pursuant to the
Offer may be withdrawn at any time prior to the Expiration Date and, unless
theretofore accepted for payment as provided in the Offer to Purchase, may also
be withdrawn at any time on or after July 5, 2004. For a withdrawal to be
effective, a written, telegraphic or facsimile transmission notice of withdrawal
must be timely received by the Depositary at one of its addresses set forth on
the back cover of the Offer to Purchase. Any such notice of withdrawal must
specify the name, address and taxpayer identification number of the person who
tendered the Shares to be withdrawn, the number of Shares to be withdrawn and
the name of the registered holder, if different from that of the person who
tendered such Shares. If certificates evidencing Shares have been delivered or
otherwise identified to the Depositary, then prior to the physical release of
such certificates, the tendering stockholder must also submit the serial numbers
shown on the particular certificates evidencing the Shares to be withdrawn, and
the signature on the notice of withdrawal must be guaranteed by an Eligible
Institution, as defined in Section 3 of the Offer to Purchase (except in the
case of Shares tendered for the account of the Eligible Institution). If Shares
have been tendered pursuant to the procedure for book-entry transfer set forth
in Section 3 of the Offer to Purchase, the notice of withdrawal must also
specify the name and number of the account at the Book-Entry Transfer Facility
(as defined in Section 2 of the Offer to Purchase) to be credited with the




withdrawn Shares. All questions as to the form and validity (including time of
receipt) of notices of withdrawal will be determined by Purchaser, in its sole
discretion, whose determination shall be final and binding. Any Shares properly
withdrawn will be deemed not validly tendered for purposes of the Offer, but may
be retendered at any subsequent time prior to the Expiration Date, or during a
Subsequent Offering Period (if available), by following any of the procedures
described in Section 3 of the Offer to Purchase.

      OneSource has provided Purchaser with OneSource's stockholder list and
security position listings for the purpose of disseminating the Offer to holders
of Shares. The Offer to Purchase, the related Letter of Transmittal and, if
required, any other relevant materials will be mailed to record holders of
Shares and will be furnished to brokers, dealers, commercial banks, trust
companies and similar persons whose names, or in the name of whose nominees,
appear on OneSource's stockholder list or, if applicable, who are listed as
participants in a clearing agency's security position listing, for subsequent
transmittal to beneficial owners of Shares by Purchaser.

      The information required to be disclosed by paragraph (d)(1) of Rule14d-6
under the Exchange Act is contained in the Offer to Purchase and is incorporated
herein by reference.

      THE OFFER TO PURCHASE AND THE RELATED LETTER OF TRANSMITTAL CONTAIN
IMPORTANT INFORMATION WHICH SHOULD BE READ CAREFULLY BEFORE ANY DECISION IS MADE
WITH RESPECT TO THE OFFER.

      Questions and requests for assistance may be directed to the Information
Agent, as set forth below. Requests for copies of the Offer to Purchase and the
related Letter of Transmittal and all other tender offer materials may be
directed to the Information Agent, and copies will be furnished promptly at
Purchaser's expense. Purchaser will not pay any fees or commissions to any
broker or dealer or any other person (other than the Depositary and the
Information Agent) for soliciting the tender of Shares pursuant to the Offer.

                     THE INFORMATION AGENT FOR THE OFFER IS:
                              D.F. KING & CO., INC.
                                 48 Wall Street
                            New York, New York 10005
                          (212) 269-5550 (call collect)
                         (800) 769-4414 (call toll-free)

May 6, 2004