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                                                                   Exhibit 31.01

CERTIFICATIONS

I, Martin Kahn, Interim Chief Executive Officer of OneSource Information
Services, Inc., certify that:

1. I have reviewed this Annual Report on Form 10-K of OneSource Information
Services, Inc.;

2. Based on my knowledge, this report does not contain any untrue statement of
a material fact or omit to state a material fact necessary to make the
statements made, in light of the circumstances under which such statements were
made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial
information included in this report, fairly present in all material respects
the financial condition, results of operations and cash flows of the registrant
as of, and for, the periods presented in this report;

4. The registrant's other certifying officer(s) and I are responsible for
establishing and maintaining disclosure controls and procedures (as defined in
Exchange Act Rules 13a-15(e) and 15d-15(e)) for the registrant and have:

           (a) Designed such disclosure controls and procedures, or caused such
           disclosure controls and procedures to be designed under our
           supervision, to ensure that material information relating to the
           registrant, including its consolidated subsidiaries, is made known
           to us by others within those entities, particularly during the
           period in which this report is being prepared;

           (b) [Paragraph omitted in accordance with United States Securities
           and Exchange Commission transition instructions contained in SEC
           Release 34-47986.]

           (c) Evaluated the effectiveness of the registrant's disclosure
           controls and procedures and presented in this report our conclusions
           about the effectiveness of the disclosure controls and procedures,
           as of the end of the period covered by this report based on such
           evaluation; and

           (d) Disclosed in this report any change in the registrant's internal
           control over financial reporting that occurred during the
           registrant's most recent fiscal quarter (the registrant's fourth
           fiscal quarter in the case of an annual report) that has materially
           affected, or is reasonably likely to materially affect, the
           registrant's internal control over financial reporting; and

5. The registrant's other certifying officer(s) and I have disclosed, based on
our most recent evaluation of internal control over financial reporting, to the
registrant's auditors and the audit committee of the registrant's board of
directors (or persons performing the equivalent functions):

           (a) All significant deficiencies and material weaknesses in the
           design or operation of internal control over financial reporting
           which are reasonably likely to adversely affect the registrant's
           ability to record, process, summarize and report financial
           information; and

           (b) Any fraud, whether or not material, that involves management or
           other employees who have a significant role in the registrant's
           internal control over financial reporting.


Date: March 29, 2004

                                            /s/ Martin Kahn
                                        ----------------------------------------
                                            Martin Kahn
                                            Interim Chief Executive Officer and
                                             Chairman of the Board of Directors