++++ SOCIAL SECURITY FOR MIGRANT WORKERS - BENEFITS - NATIONAL RULES AGAINST OVERLAPPING - CONCEPT - RULE UNDER WHICH THE BASIC AMOUNT FOR CALCULATING A PERSON' S RETIREMENT PENSION IS REDUCED BY REASON OF A PENSION RECEIVED BY THAT PERSON' S SPOUSE - EXCLUDED ( COUNCIL REGULATION NO 1408/71, ART . 12 ( 2 ) )