Artikel 12

1. Any State Member of the Council and any State Member of the United Nations or its specialised agencies may become a Contracting Party to the present Convention:
(a) by signing it without reservation of ratification;
(b) by depositing an instrument of ratification after signing it subject to ratification; or
(c) by acceding to it.
2. The present Convention shall be open until 30th September, 1965, for signature at the Headquarters of the Council in Brussels, by the States referred to in paragraph 1 of this Article. Thereafter, it shall be open for their accession.
3. Any State, not being a Member of the Organisations referred to in paragraph 1 of this Article, to which an invitation to that effect has been addressed by the Secretary General of the Council at the request of the Contracting Parties, may become a Contracting Party to the present Convention by acceding thereto after its entry into force.
4. The instruments of ratification or accession shall be deposited with the Secretary General of the Council.