Commission Regulation (EEC) No 946/83 of 21 April 1983 amending Regulation (EEC) No 1573/80 laying down provisions for the implementation of Article 5 (2) of Council Regulation (EEC) No 1697/79 on the post-clearance recovery of import duties or export duties which have not been required of the person liable for payment on goods entered for a customs procedure involving the obligation to pay such duties