++++ 1 . CUSTOMS DUTIES - CHARGES HAVING EQUIVALENT EFFECT - CONCEPT ( EEC TREATY, ARTICLE 13 ) 2 . CUSTOMS DUTIES - CHARGES HAVING EQUIVALENT EFFECT - ELIMINATION - OBLIGATIONS OF MEMBER STATES - NATURE ( EEC TREATY, ARTICLE 13 ) 3 . CUSTOMS DUTIES - CHARGES HAVING EQUIVALENT EFFECT - ELIMINATION - TIME-TABLE - DETAILED RULES OF PROGRESSION - POWERS OF THE COMMISSION ( EEC TREATY, ARTICLES 13 AND 14 ) 4 . EUROPEAN ECONOMIC COMMUNITY - LEGAL SYSTEM OF THE COMMUNITY - COMMUNITY INSTITUTION - FAILURE TO FULFIL ITS OBLIGATIONS - MEMBER STATE - RETALIATORY MEASURES - PROHIBITION