[ REPUBLIC OF ANGOLA Article 37 (Licensing marks) 1. The holder of a mark registration may, by an agreement in writing, grant a license to exploit some or all the products in some parts of Angola or throughout the country. 2. Any license agreement must provide for the efficient monitoring by the licensor of the quality of the licensee’s products or services in relation to which the mark is used, failing which the contract shall be null and void. 3. Unless otherwise provided in the license agreement, the licensee shall enjoy all the powers attributed to the registration holder. 4. The right arising from the exploitation license cannot be alienated without the express written authorization of the registration holder, unless otherwise provided in the license agreement. 5. Collective marks cannot be, unless where specifically provided by law or by the statutes of their holder entities. Article 38 (Term of registrations - renewal) 1. The registration of a mark shall be valid for a period of ten years from the date of filing of the registration application. 2. Registration may be renewed for consecutive ten-year periods on payment of the prescribed fee, or up to four months after the term. 3. Where the applicant proves that a valid reason prevented him from filing a renewal application within the legally-prescribed period, the revalidation of a mark registration may also be requested, within a period of one year from the end of its period of validity and on payment of the required fees. Article 39 (Lapse of a registration) The registration of a mark shall lapse in the following situations: a) on the expiration of the period of legal protection, where it has not be renewed; b) where the owner expressly renounces it in a duly authenticated statement, without prejudice to third parties;