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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term of this agreement HGF shall have the right, upon written approval of NVOS, to assign, transfer or sell all or part of their interest in this agreement. ARTICLE 20 - BEST EFFORTS 20.1 NVOS and HGF covenant and agree to make their best efforts to fully develop the Primary Projects as well as all projects associated to this agreement as per this agreement at all times faithfully, honestly and diligently perform or cause to be performed their obligations hereunder and to continuously exert best efforts to promote and enhance the business and in that regards they hereby covenant and agree, so long as this Agreement shall remain in effect, to operate the business, as to preserve, maintain and enhance the reputation of NVOS and HGF through the Company. ARTICLE 21 - DISPUTES 21.1 The Parties shall negotiate in good faith and make every effort to settle any dispute, or claim, that may arise out of, or relate to, the Agreement. If agreement cannot be reached, an aggrieved Party shall, if he intends to proceed further in terms of Section 21.2 hereof, advise all other Parties in writing that negotiations have failed and that he intends to refer the matter to mediation in terms of Section 21.2. 21.2 Not earlier than ten (10) working days after having advised the other Party, in terms of Section 21.2, that negotiations in regard to a dispute have failed, an aggrieved Party may require that the dispute be referred, without legal representation, to mediation by a single mediator. The mediator shall be selected by agreement between the Parties. The costs of the mediation shall be borne equally by the Parties. The mediator shall convene a hearing of the Parties and may hold separate discussions with either Party and shall assist the Parties in reaching a mutually acceptable settlement of their differences through means of reconciliation, interpretation, clarification, suggestion and advice. The Parties shall record such agreement in writing and thereafter they shall be bound by such agreement. The mediator is authorised to end the mediation process whenever in his opinion further efforts at mediation would not contribute to a resolution of the dispute between the Parties. 21.3 Where a dispute or claim is not resolved by mediation, it shall be referred to arbitration by a single arbitrator to be selected by agreement between the Parties. The Party requiring referral to arbitration shall notify the other Party, in writing, thereof, not later than thirty (30) calendar days after the mediator has expressed his opinion, failing which the mediator's opinion shall be deemed to have been accepted by the Parties and shall be put into effect. Arbitration shall be conducted in accordance with the provisions of the Arbitration Act No. 42 of 1965, as amended, and in accordance with such procedure as may be agreed by the Parties or, failing such agreement, in accordance with the rules for the Conduct of Arbitrations published by the Association of Arbitrators and current at the date that the arbitrator is appointed. The decisions of the arbitrator shall be final and binding on the Parties, shall be carried into immediate effect and, if necessary, be made an order of any court of competent jurisdiction. ARTICLE 22 - INDEMNIFICATION 22.1 The Parties agree to mutually defend, indemnify and save one another harmless from and against any claims, demands, actions, losses, damages, costs, charges, liabilities and any expenses, including legal fees of whatever kind arising out of or in connection with each parties' activities conducted pursuant to this Agreement. ARTICLE 23 - CONFORMITY WITH LAWS 23.1 In this Agreement, the singular includes the plural and the masculine includes the feminine and neuter and vice versa unless the context otherwise requires. 23.2 If any provision or part of any provision in this Agreement is void for any reason or found to be unenforceable, it may be severed without affecting the validity and enforceability of the balance of the Agreement. 23.3 This Agreement binds and benefits the parties and their respective heirs, executors, administrators, personal representatives, successors and assigns. 23.4 This Agreement contains the sole and entire agreement between the parties and supersedes any and all other agreements, both verbal and written, between them. 23.5 The parties agree that neither of them has made any representations with respect to the subject matter of this Agreement, or any representations inducing the execution and delivery hereof, except such representations as are specifically set forth herein. ARTICLE 24 - CONFIDENTIALITY 24.1 The parties shall keep confidential all
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Extract the exact clause related to "Volume Restriction" from the excerpt above.