++++ 1 . PROCEDURE - REFERENCES FOR PRELIMINARY RULING - JURISDICTION OF THE COURT - LIMITS - TASK OF NATIONAL COURTS OR TRIBUNALS ( EEC TREATY, ARTICLE 177 ) 2 . PROCEDURE - REFERENCES FOR PRELIMINARY RULING - REFERENCE TO THE COURT BY A NATIONAL COURT OR TRIBUNAL - CONDITIONS ( EEC TREATY, ARTICLE 177 ) 3 . PROCEDURE - REFERENCES FOR PRELIMINARY RULING - PARTICIPATION IN PROCEEDINGS - LIMITS ( STATUTE OF COURT OF JUSTICE OF THE EEC, ARTICLE 20 ) 4 . SOCIAL SECURITY FOR MIGRANT WORKERS - WAGE - EARNERS - ASSIMILATED WORKERS - CONCEPT - CRAFTSMEN - INSURANCE PERIODS - CONCEPT ( REGULATION NO 3 OF THE COUNCIL CONCERNING SOCIAL SECURITY FOR MIGRANT WORKERS ) 5 . SOCIAL SECURITY FOR MIGRANT WORKERS - REGULATION NO 4 - ANNEXES 7 AND 9 - DECLARATORY NATURE