Article 51 2.

The periods of insurance completed under a special scheme of a Member State shall be taken into account for the purposes of providing the benefits of the general scheme or, failing that, of the scheme applicable to manual or clerical workers, as the case may be, of another Member State, provided that the person concerned had been affiliated to one or other of those schemes, even if those periods have already been taken into account in the latter Member State under a special scheme.