Convention and to any Protocol, subject to prior approval by three-fourths of the Contracting Parties to the Protocol concerned. 3. Instruments of accession shall be deposited with the Depositary. Article 27 Entry into force 1. This Convention shall enter into force on the same date as the Protocol first entering into force. 2. The Convention shall also enter into force with regard to the States, the European Economic Community and any regional economic grouping referred to in Article 24 if they have complied with the formal requirements for becoming Contracting Parties to any other Protocol not yet entered into force. 3. Any Protocol to this Convention, except as otherwise provided in such Protocol, shall enter into force on the 30th day following the date of deposit of at least six instruments of ratification, acceptance, or approval of, or accession to such Protocol by the Parties referred to in Article 24. 4. Thereafter, this Convention and any Protocol shall enter into force with respect to any State, the European Economic Community and any regional economic grouping referred to in Article 24 on the 30th day following the date of deposit of the instruments of ratification, acceptance, approval or accession. Article 28 Withdrawal 1. At any time after three years from the date of entry into force of this Convention, any Contracting Party may withdraw from this Convention by giving written notification of withdrawal. 2. Except as may be otherwise provided in any Protocol to this Convention, any Contracting Party may, at any time after three years from the date of entry into force of such Protocol, withdraw from such Protocol by giving written notification of withdrawal. 3. Withdrawal shall take effect 90 days after the date on which notification of withdrawal is received by the Depositary. 4. Any Contracting Party which withdraws from this Convention shall be considered as also having withdrawn from any Protocol to which it was a Party. 5. Any Contracting Party which, upon its withdrawal from a Protocol, is no longer a Party to any Protocol to this Convention, shall be considered as also having withdrawn from this Convention. Article 29 Responsibilities of the Depositary 1. The Depositary shall inform the Contracting Parties, any other Party referred to in Article 24, and the Organization:(i) of the signature of this Convention and of any Protocol thereto, and of the deposit of instruments of ratification, acceptance, approval or accession in accordance with Articles 24, 25 and 26; (ii) of the date on which the Convention and any Protocol will come into force in accordance with the provisions of Article 27; (iii) of notifications of withdrawal made in accordance with Article 28; (iv) of the amendments adopted with respect to the Convention and to any Protocol, their acceptance by the Contracting Parties and the date of entry into force of those amendments in accordance with the provisions of Article 16; (v) of the adoption of new Annexes and of the amendment of any Annex in accordance with Article 17; (vi) of declarations recognizing as compulsory the application of the arbitration procedure mentioned in paragraph 3 of Article 22. 2. The original of this Convention and of any Protocol thereto shall be deposited with the Depositary, the Government of Spain, which shall send certified copies thereof to the Contracting Parties, to the Organization, and to the Secretary-General of the United Nations for registration and publication in accordance with Article 102 of the United Nations Charter. In witness whereof the undersigned, being duly authorized by their respective Governments, have signed this Convention. Done at Barcelona on 16 February 1976 in a single copy in the Arabic, English, French and Spanish languages, the four texts being equally authoritative. ANNEX A ARBITRATION Article 1 Unless the Parties to the dispute otherwise agree, the arbitration procedure shall be conducted in accordance with the provisions of this Annex. Article 2 1. At the request addressed by one Contracting Party to another Contracting Party in accordance with the provisions of paragraph 2 or paragraph 3 of Article 22 of the Convention, an arbitral tribunal shall be constituted. The request for arbitration shall state the subject matter of the application including, in particular, the articles of the Convention or the Protocols, the interpretation or application of which is in dispute. 2. The claimant party shall inform the Organization that it has requested the setting up of an arbitral tribunal, stating the name of the other Party to the dispute and articles of the Convention or the Protocols the interpretation or application of which is in its opinion in dispute. The Organization shall forward the information thus received to all Contracting Parties to the Convention. Article 3 The arbitral tribunal shall consist of three members : each of the Parties to the dispute shall appoint an arbitrator ; the two arbitrators so appointed shall designate by common agreement the third arbitrator who shall be the chairman of the tribunal. The latter shall not be a national of one of the Parties to the dispute, nor have his usual place of residence in the territory of one of these Parties, nor be employed by any of them, nor have dealt with the case in any other