TREATY ESTABLISHING THE EUROPEAN ECONOMIC COMMUNITY, PART TWO - FOUNDATIONS OF THE COMMUNITY, TITLE I - FREE MOVEMENT OF GOODS, CHAPTER 1: THE CUSTOMS UNION, SECTION 2: SETTING UP OF THE COMMON CUSTOMS TARIFF, ARTICLE 28
TREATY ESTABLISHING THE EUROPEAN ECONOMIC COMMUNITY, PART SIX - GENERAL AND FINAL PROVISIONS, ARTICLE 235