JuriSTEP INTELLECTUAL PROPERTY LAW concerning products placed on the market in Sao Tome and Principe by the owner of the registry or with the his consent. 4. The registry of a mark is effective for ten years counting from the date of deposit of the registry application. 5. a) Upon request, the registry of a mark can be renewed for consecutive periods of ten years each, provide the registry owner pays a renewal fee. b) An extension of term of six months shall be granted for the payment of the renewal fee after expiration, subject to a surcharge. Article 20 Annulment 1. Any person can submit to the National Service for Intellectual Property an application for the annulment of registry of a mark. 2. The National Service for Intellectual Property annuls the registry if the application offers evidence that any of the exclusions of Article 17 is applicable or that he is the owner of a mark benefiting of a date of deposit or of priority and that the mark, which annulment of registry he is requesting, is an infringement of a prior mark, according to Article 19, paragraph 1. 3. The National Service for Intellectual Property annuls the registry if verifies there is a violation of the Article l6, paragraph 1. 4. The annulment of the registry of a mark is considered to be effective on the date of the registry and shall be published as soon as possible. 5. Any person interested may request to the Director of Industry the annulment of a mark, for a product or service for which it has been registered, due to the fact that the mark, after its registry and up to a month before the application has not been used by the owner of the registry, neither by any person who has acquired the right to use the mark, during a not-interrupted period of five years. However, the mark is not annulled if it is proved that special circumstances made its use impossible and that there was no intention not to use it or to abandon it concerning the products or services in question. Article 21 Collective marks 1. Without prejudice of paragraph 2, Articles 17, 18, paragraph 1 and 20 are applicable to collective marks. 2. a) In the registry application, the collective mark shall be identified as such and a copy of the regulation of use of the mark shall be joint to 14