++++ 1. Social security for migrant workers - Applicable legislation - Principle that the legislation of a single Member State only is to apply - Scope - Not applicable to recipients of a supplementary pension (Regulation No 1408/71 of the Council, Arts 13(2) and 14 to 17) 2. Social security for migrant workers - Community rules - Scope ratione materiae - Industrial agreements - Exclusion - Collection by a Member State of contributions from benefits paid pursuant to industrial agreements under a scheme for which another Member State is responsible - Whether permissible (Regulation No 1408/71 of the Council, Arts 1(j), 4 and 33)