system: You are a contract-analysis assistant performing a span-extraction task. You are given an excerpt from a commercial contract and the name of a clause type to locate within it.

Return the exact text of the requested clause, copied verbatim from the excerpt — identical wording and punctuation, with no paraphrasing, summarising, explanation, or added commentary.

The excerpt is one window of a much longer contract and often will not contain the requested clause. If the requested clause does not appear in this excerpt, respond with exactly: Not found.

Output only the extracted clause text, or the exact string `Not found.` — nothing else.

user: Contract excerpt:
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to reasonably agree on whether or how to amend Section 7.1.2 [Co-Branded Equipment Listings], either party shall have the right to immediately terminate the rights and obligations of the parties under Sections 2 and 7.1.2 [Co-Branded Equipment Listings] with respect to the Co-Branded Equipment Listings and PaperExchange Equipment Content; provided, however, that all other rights and obligations under this Agreement (including the rights and obligations of the parties under Sections 4.3 [Non-Competition] and 5.8 [Non-Competition]) shall continue in full force and effect unless and until terminated in accordance with Section 8. The parties understand and agree that termination of the rights and obligations of the parties under Sections 2 and 7.1.2 [Co-Branded Equipment Listings] in accordance with this Section 7.1.3 [Review of Payments] shall not permit either party to terminate this Agreement pursuant to Section 8.2 [Termination for Cause]. 7.1.4. Professional e-Bookstore Sales. VerticalNet will pay PaperExchange ***** of the gross sales of the Professional e-Bookstore on Pulp and Paper Online that originated from the PaperExchange Site. 7.2. Advertising Revenue. 7.2.1. During the Term, VerticalNet shall not share any revenue derived from advertisements hosted on Pulp and Paper Online or any other VerticalNet Site with PaperExchange; provided, however, that if PaperExchange brings VerticalNet a Qualified Lead * Confidential Treatment Requested: material has been omitted and filed separately with the Commission 11 (as defined below) for a new customer that turns into a sale of advertising on Pulp and Paper. Online or Packaging Online, including, without limitation, the Co-Branded Sites, VerticalNet shall pay to PaperExchange a commission of ***** of the Net Advertising Revenue resulting from such sale of advertising, with the exception that if such advertising is on the Co-branded Career Center, VerticalNet shall pay PaperExchange a commission of ***** of the Net Advertising Revenue resulting from such sale of advertising. As used in this Section 7.2.1 [Advertising Revenue], a "Qualified Lead" shall mean a customer referred to VerticalNet by PaperExchange that is not, at the time of referral, a customer of VerticalNet, and which customer has agreed to place an advertisement on Pulp and Paper Online or Packaging Online on the terms and conditions contained in VerticalNet's then current advertising policies. 7.2.2. PaperExchange shall pay to VerticalNet a commission of ***** of the Net Advertising Revenue received during the Term for advertisements located on the Third Party Advertising Allocation of the PaperExchange Site. 7.2.3. If PaperExchange sells advertising to a third party on the PaperExchange Site independently from VerticalNet, PaperExchange shall pay to VerticalNet a commission of ***** of the Net Advertising Revenue resulting from such advertising during the Term; provided, however, that if PaperExchange previously rejected advertising by such party when proposed by VerticalNet pursuant to Section 4.1 [Advertisements on the PaperExchange Site], or terminated without cause a prior agreement with such third party that had resulted from such a proposal by VerticalNet, then PaperExchange shall pay ***** of the Net Advertising Revenue resulting from such advertising during the Term to VerticalNet. PaperExchange shall provide prompt notice to VerticalNet of each advertiser that has agreed with PaperExchange to place an advertisement on a page of the PaperExchange Site. 7.3. Fees. In consideration of VerticalNet's agreement to enter into an exclusivity and non-competition agreement herein, in conjunction with the other obligations under this Agreement, PaperExchange shall make the following payments to VerticalNet upon the earlier of (a) December 31, 1999 and (b) the receipt by PaperExchange of an aggregate of ***** in additional funding: 7.3.1. a ***** one-time, non-refundable fee in consideration of the execution of this Agreement; 7.3.2. a ***** one-time, non-refundable fee in consideration of the design, development and implementation of the Co-Branded Career Center as described in Section 2; and 7.3.3. ***** in consideration of the design, development and implementation of the Co-Branded Equipment Listings Site as described in Section 2. 7.4. Revenue Sharing. After PaperExchange has generated PaperExchange Revenue equal to *****, PaperExchange shall pay an amount equal to ***** of the PaperExchange Revenue to VerticalNet; provided, however, that if, in any given calendar year, VerticalNet receives ***** pursuant to this Section 7.4 [Revenue Sharing], the percentage of PaperExchange Revenue that PaperExchange shall pay to VerticalNet for the remainder of such calendar year shall be reduced to *****; and provided further, however, that if, in any given calendar year, VerticalNet receives * Confidential Treatment Requested: material has been omitted and filed separately with the Commission. 12 ***** in the aggregate pursuant to this Section 7.4 [Revenue Sharing], the percentage of PaperExchange Revenue that PaperExchange shall
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Extract the exact clause related to "Parties" from the excerpt above.