Paragraph
Subject to the provisions of Articles 17 to 20, the provisions of this Article shall apply for the purpose of determining entitlement to retirement pension, including any increase for dependants, in respect of a person under the legislation of any part of either Party under which there is no entitlement in respect of that person in accordance with the provisions of Article 15.
In accordance with the provisions of Article 11, the competent authority of any part of either Party shall determine:
the amount of the theoretical pension which would be payable if all the relevant insurance periods completed under the legislation of both Parties had been completed under its own legislation;
the proportion of such theoretical pension which bears the same relation to the whole as the total of the insurance periods completed under the legislation of that part of either Party bears to the total of all the relevant insurance periods completed under the legislation of both Parties.