1 . SOCIAL SECURITY FOR MIGRANT WORKERS - LEGISLATION OF A MEMBER STATE WITHIN THE MEANING OF ARTICLE 1 ( J ) OF REGULATION NO 1408/71 - CONCEPT 2 . SOCIAL SECURITY FOR MIGRANT WORKERS - RIGHTS ACQUIRED UNDER THE LEGISLATION OF A MEMBER STATE - RECIPIENT - EMPLOYMENT EXCLUSIVELY IN A NON-METROPOLITAN TERRITORY - RESIDENCE CLAUSE - WAIVER - APPLICATION ( REGULATION NO 1408/71 , ARTICLE 10 ( 1 ))