(a) aggregation, for the purpose of acquiring and retaining the right to benefit and of calculating the amount of benefit, of all periods taken into account under the laws of the several countries;
(a) go gcomhshuimeofar, d'fhonn an ceart chun sochair a fháil agus a choinneáil agus méid an tsochair a ríomh, na tréimhsí uile a chuirtear san áireamh faoi dhlíthe na dtíortha éagsúla;