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:
"""
after the Effective Date. The Links shall remain on the Sites during the Term; provided, however, that such Links may be removed or relocated if the Parties mutually agree thereto. 8.4 NEWSLETTERS. 8.4.1 NEOFORMA NEWSLETTERS. If Neoforma distributes a newsletter to its users or customers, Neoforma shall promote the VerticalNet Auction, the Co-Branded Career Center and the Co-Branded Training and Education Center in each such newsletter, in a manner consistent with the manner in which other third party promotions are set forth in such newsletters. 12 13 8.4.2 VERTICALNET NEWSLETTERS. VerticalNet shall allow Neoforma to place sponsorships at no additional charge for Neoforma Shop, Neoforma Plan or Neoforma Auction in the VerticalNet newsletter distributed to its subscriber base two times during each calendar month, in a manner consistent with the manner in which other third party sponsorships are set forth in such newsletters. 8.5 LINKS. 8.5.1 Throughout the first six months after the Effective Date, VerticalNet shall place button Links to Neoforma Shop or Neoforma Auction on (a) [*] of all available third-party advertising inventory on the home pages of the VerticalNet Medical Online Communities. Thereafter, VerticalNet shall place button Links to Neoforma Shop or Neoforma Auction on unsold third-party advertising inventory (up to [*] of the total third party advertising inventory) on the home pages of the VerticalNet Medical Online Communities as frequently as VerticalNet places internal advertisements on such advertising inventory and (b) the site located at www.meddeals.com. 8.5.2 Throughout the Term, VerticalNet shall place button Links to Neoforma Shop or Neoforma Auction on (a) the VerticalNet Buyer's Guides (as described in Section 2.7 [MEDICAL PRODUCTS]) and VerticalNet Auction, and (b) the "News Analysis," "Product Center" and "Discussion Forums" portions of the VerticalNet Medical Online Communities. 9. INTELLECTUAL PROPERTY 9.1 Except as set forth in Section 2.10 [MEDICAL PRODUCTS], nothing in this Agreement shall be construed as preventing VerticalNet from implementing VerticalNet Links on any other Site. 9.2 Except as set forth in Sections 3.8 [LABORATORY PRODUCTS] and 5.8 [CO-BRANDED TRAINING AND EDUCATION SITE], nothing in this Agreement shall be construed as preventing Neoforma from implementing Neoforma Links on any other Site. 9.3 VerticalNet hereby grants to Neoforma a non-exclusive, non-transferable, royalty-free, right and license to link to the VerticalNet Sites through a VerticalNet Link. VerticalNet shall furnish Neoforma with a full color representation of each VerticalNet Link at least two days prior to its scheduled placement on a page of the Neoforma Site. If VerticalNet subsequently modifies any VerticalNet Link or the URL associated with such VerticalNet Link, it shall furnish a representation of same to Neoforma, which Neoforma shall substitute for the prior version within two days after receipt thereof. VerticalNet shall have final approval over all VerticalNet Links on the Neoforma Site. 9.4 Neoforma hereby grants VerticalNet a non-exclusive, non-transferable, royalty-free, right and license to link to the Neoforma Sites through a Neoforma Link. Neoforma shall furnish VerticalNet with a full color representation of each Neoforma Link at least two days prior to its scheduled placement on the Co-Branded Sites or a VerticalNet Medical Online Community. If Neoforma subsequently modifies any Neoforma Link or the URL associated with such Neoforma Link, it shall furnish a representation of same to VerticalNet, which VerticalNet shall substitute for the prior version within two days after receipt thereof. Neoforma shall have final approval over all Neoforma Links on the Co-Branded Sites or a VerticalNet Medical Online Community. *Certain information on this page has been omitted and filed separately with the Source: NEOFORMA INC, S-1/A, 12/2/1999 Commission. Confidential treatment has been requested with respect to the omitted portions. 13 14 9.5 Except for the express rights granted to Neoforma under this Agreement, Neoforma acknowledges and agrees that the Intellectual Property of VerticalNet is and shall remain the sole property of VerticalNet and nothing in this Agreement shall confer in Neoforma any right of ownership or license rights in VerticalNet's Intellectual Property. In addition, Neoforma shall not now or in the future contest the validity of VerticalNet's Intellectual Property. 9.6 Except for the express rights granted to VerticalNet under this Agreement, VerticalNet acknowledges and agrees that the Intellectual Property of Neoforma is and shall remain the sole property of Neoforma and nothing in this Agreement shall confer in VerticalNet any right of ownership or license rights in Neoforma's Intellectual Property. In addition, VerticalNet shall not now or in the future contest the validity of Neoforma's Intellectual Property. 9.7 Neoforma agrees to use the VerticalNet Marks in accordance with the terms of
"""

Extract the exact clause related to "Covenant Not To Sue" from the excerpt above.

assistant: In addition, Neoforma shall not now or in the future contest the validity of VerticalNet's Intellectual Property.