6 Article 17 1. At the time of signature, ratification or accession any State may make a reservation in respect of articles 11, 14 or 15. 2. No other reservations to this Convention shall be admissible. Article 18 1. This Convention shall enter into force two years after the date of the deposit of the sixth instrument of ratification or accession. 2. For each State ratifying or acceding to this Convention after the deposit of the sixth instrument of ratification or accession, it shall enter into force on the ninetieth day after the deposit by such State of its instrument of ratification or accession or on the date on which this Convention enters into force in accordance with the provisions of paragraph 1 of this article, whichever is the later. Article 19 1. Any Contracting State may denounce this Convention at any time by a written notification addressed to the Secretary-General of the United Nations. Such denunciation shall take effect for the Contracting State concerned one year after the date of its receipt by the Secretary-General. 2. In cases where, in accordance with the provisions of article 15, this Convention has become applicable to a non-metropolitan territory of a Contracting State, that State may at any time thereafter, with the consent of the territory concerned, give notice to the Secretary-General of the United Nations denouncing this Convention separately in respect to that territory. The denunciation shall take effect one year after the date of the receipt of such notice by the Secretary-General, who shall notify all other Contracting States of such notice and the date of receipt thereof. Article 20 1. The Secretary-General of the United Nations shall notify all Members of the United Nations and the non-member States referred to in article 16 of the following particulars: ( a ) Signatures, ratifications and accessions under article 16; ( b ) Reservations under article 17; ( c ) The date upon which this Convention enters into force in pursuance of article 18; ( d ) Denunciations under article 19. 2. The Secretary-General of the United Nations shall, after the deposit of the sixth instrument of ratification or accession at the latest, bring to the attention of the General Assembly the question of the establishment, in accordance with article 11, of such a body as therein mentioned. Article 21 This Convention shall be registered by the Secretary-General of the United Nations on the date of its entry into force. In witness whereof the undersigned Plenipotentiaries have signed this Convention. Done at New York, this thirtieth day of August, one thousand nine hundred and sixty-one, in a single copy, of which the Chinese, English, French, Russian and Spanish texts are equally authentic and which shall be deposited in the archives of the United Nations, and certified copies of which shall be delivered by the Secretary-General of the United Nations to all members of the United Nations and to the non-member States referred to in article 16 of this Convention.