TAX PROVISIONS - HARMONIZATION OF LAWS - TURNOVER TAXES - COMMON SYSTEM OF VALUE ADDED TAX - DIFFERENT ACCOUNTING PERIODS AND TIME-LIMITS FOR PAYMENT PRESCRIBED BY A MEMBER STATE FOR VAT ON IMPORTS AND VAT ON DOMESTIC TRANSACTIONS - PERMISSIBILITY - COMPATIBILITY WITH ARTICLE 95 OF THE TREATY ( EEC TREATY , ART . 95 ; COUNCIL DIRECTIVE 77/388 )