1 . MEASURES ADOPTED BY INSTITUTIONS - DIRECTIVES - EFFECT - NON-IMPLEMENTATION BY A MEMBER STATE - RIGHT OF INDIVIDUALS TO RELY UPON THE DIRECTIVE - CONDITIONS ( EEC TREATY , ART . 189 ) 2 . MEASURES ADOPTED BY INSTITUTIONS - DIRECTIVES - DIRECTIVE CONFERRING A MARGIN OF DISCRETION ON THE MEMBER STATES - PROVISIONS WHICH ARE SEVERABLE AND MAY BE RELIED UPON BY INDIVIDUALS ( EEC TREATY , ART . 189 ; COUNCIL DIRECTIVE 77/388 ) 3 . TAX PROVISIONS - HARMONIZATION OF LAWS - TURNOVER TAX - COMMON SYSTEM OF VALUE-ADDED TAX - EXEMPTIONS CONFERRED BY THE SIXTH DIRECTIVE - TAXABLE PERSONS ' RIGHT OF OPTION - IMPLEMENTATION - POWERS OF THE MEMBER STATES - LIMITS ( COUNCIL DIRECTIVE 77/388 , ART . 13 B AND C ) 4 . TAX PROVISIONS - HARMONIZATION OF LAWS - TURNOVER TAX - COMMON SYSTEM OF VALUE-ADDED TAX - EXEMPTIONS CONFERRED BY THE SIXTH DIRECTIVE - EFFECTS WITHIN THE SYSTEM OF VALUE-ADDED TAX ( COUNCIL DIRECTIVE 77/388 ) 5 . TAX PROVISIONS - HARMONIZATION OF LAWS - TURNOVER TAX - COMMON SYSTEM OF VALUE-ADDED TAX - EXEMPTIONS CONFERRED BY THE SIXTH DIRECTIVE - EXEMPTION OF TRANSACTIONS CONSISTING OF THE NEGOTIATION OF CREDIT - POSSIBILITY OF INDIVIDUALS ' RELYING UPON THE RELEVANT PROVISION WHERE THE DIRECTIVE HAS NOT BEEN IMPLEMENTED - CONDITIONS ( COUNCIL DIRECTIVE 77/388 , ART . 13 B ( D ) 1 )