Artikel XXI

1. This Agreement shall come into force not earlier than 1 January 1957, when instruments of acceptance or of accession have been deposited by Governments responsible in the aggregate for initial assessments of not less than ninety per cent of the initial maximum cost figure laid down in Article V. As regards those Governments, deposit of an instrument of acceptance or of accession shall be deemed to constitute consent to the system of assessments, payments and adjustments under this Agreement for the period between 1 January 1957 and the entry into force of this Agreement.
2. As regards any Government whose instrument of acceptance or of accession is deposited after the entry into force of this Agreement, the Agreement shall come into force on the date of such deposit. Each such Government shall consent to the system of assessments, payments and adjustments under this Agreement with effect at least from the beginning of the calendar year during which the instrument of acceptance or of accession is deposited. Each such Government may elect to be assessed for its appropriate share of the actual approved costs of any Services in respect of which the provisions of Article VI have been applied and as to which, at the date of accession of such Government, the consents of all Contracting Governments have not been given.