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:
"""
NTC has made sales to the customer (including its affiliates) referred to NTC by ALFA AESAR within a period of twelve (12) months before ALFA AESAR's referral under Section 6.1, NTC shall pay ALFA AESAR a commission at the rate of [***] on the Net Sales made to each such customer so referred to NTC under Section 6.1. NTC shall pay ALFA AESAR on a monthly basis for all such commissions for a period of three (3) years from the date of such referred customer's first order of Products or Custom Services from NTC. *** CONFIDENTIAL TREATMENT REQUESTED—This confidential portion has been omitted from this document and filed separately with the Commission. 4 6.3 NTC shall maintain adequate records of its invoices and accounting records reflecting all such sales in accordance with standard accounting principles. Within twelve (12) months after the date this Agreement has been terminated by the parties, ALFA AESAR may engage an independent certified public accounting firm reasonably acceptable to NTC to audit the NTC invoices and accounting records pertaining to those customers identified as referrals under Section 6.1 at NTC's offices during normal business hours by providing thirty (30) days advance notice of such audit for the purpose of determining the accuracy of the commissions paid or payable to ALFA AESAR hereunder. NTC shall promptly pay ALFA AESAR for any deficiencies between the commission earned and the commission paid to ALFA AESAR. 7. Trademarks. 7.1 Each party hereby covenants and agrees that the Trademarks, copyrights and other proprietary rights of the other party are and shall remain the sole and exclusive property of that party and neither party shall hold itself out as having any ownership rights with respect to or, except as specifically granted hereunder, in any other rights therein. Any and all goodwill associated with any such rights shall inure directly and exclusively to the benefit of the owner thereof. 7.2 ALFA AESAR hereby grants to NTC a limited non-exclusive license to use the ALFA AESAR Trademarks in the form provided by ALFA AESAR during the Term of this Agreement in accordance with the terms set forth herein. Such license is granted solely in connection with NTC's rights and obligations under this Agreement and, in particular, for the purpose of licensing NTC to use the ALFA AESAR Trademark on the NTC web site as expressly contemplated herein for referral of customers of Research Quantities to ALFA AESAR and is a link/navigational button to the ALFA AESAR Site. All such uses will be subject to ALFA AESAR's approval as to the manner and/or form of use. NTC will not be allowed to use or reproduce the ALFA AESAR Trademark for any other purpose, including the general promotion of the NTC Site, without the prior written approval of ALFA AESAR. 7.3 NTC hereby grants ALFA AESAR a limited non-exclusive license to use, exhibit, excerpt, reproduce, publish, publicly perform and transmit via the Internet and otherwise use the NTC Trademarks in substantially the form as NTC may provide to ALFA AESAR from time to time during the Term of this Agreement in accordance with the terms set forth herein. Such license is granted solely in connection with ALFA AESAR's rights and obligations under this Agreement and, in particular, for the purpose of licensing ALFA AESAR to use the NTC Trademarks in ALFA AESAR's marketing, sales and distribution materials relative to the Products, including without limitation on the ALFA AESAR's Web site as a link/navigational button to the NTC Web site as posted by NTC. All such uses shall be subject to NTC's prior written approval as to manner and/or form of use. 7.4 Except as provided for in this Agreement, each party understands that the Web site links contemplated above to the other party's site may not be used in any manner to provide viewers access to the other party's Site via any caching, framing, layering or other techniques that cause 5 intermediate copying of the other party's Site (or elements thereof) or display of the other party's site or portions thereof in any manner unintended by the owner of the Site. 7.5 Upon termination of this Agreement, ALFA AESAR may continue to advertise and promote the Products, using the NTC's Trademarks and NTC content until ALFA AESAR's inventory depletion. 8. Training; Product Material. 8.1 NTC will provide training to ALFA AESAR's personnel on ALFA AESAR's premises as reasonably necessary, but no less than once annually, at mutually agreed upon times and dates to provide ALFA AESAR's
"""

Extract the exact clause related to "Audit Rights" from the excerpt above.

assistant: Within twelve (12) months after the date this Agreement has been terminated by the parties, ALFA AESAR may engage an independent certified public accounting firm reasonably acceptable to NTC to audit the NTC invoices and accounting records pertaining to those customers identified as referrals under Section 6.1 at NTC's offices during normal business hours by providing thirty (30) days advance notice of such audit for the purpose of determining the accuracy of the commissions paid or payable to ALFA AESAR hereunder.