1 . SOCIAL SECURITY FOR MIGRANT WORKERS - SOCIAL SECURITY CONTRIBUTIONS - REIMBURSEMENT - REGULATIONS NOS 3 AND 1408/71 - MATTERS COVERED - EXTENT - SOCIAL SECURITY SCHEMES TAKEN IN THEIR ENTIRETY ( REGULATION NO 3 OF THE COUNCIL , ARTICLE 2 ; REGULATION NO 1408/71 OF THE COUNCIL , ARTICLE 4 ) 2 . SOCIAL SECURITY FOR MIGRANT WORKERS - SOCIAL SECURITY CONTRIBUTIONS - REIMBURSEMENT - REGULATION NO 3 - NO SPECIFIC RULE - APPLICATION OF THE GENERAL RULES - REGULATION NO 1408/71 - SPECIFIC RULE - TEMPORAL APPLICATION - NOT RETROACTIVE ( REGULATION NO 3 OF THE COUNCIL ; REGULATION NO 1408/71 , ARTICLE 10 ( 2 )) 3 . SOCIAL SECURITY FOR MIGRANT WORKERS - SOCIAL SECURITY CONTRIBUTIONS - REIMBURSEMENT - LEGAL OPTIONS UNDER THE LEGISLATION OF A MEMBER STATE - REGULATION NO 3 - NO EXPRESS PROVISIONS - EXERCISE OF OPTIONS ( REGULATION NO 3 OF THE COUNCIL )