Commission Regulation (EEC) No 815/91 of 2 April 1991 amending Regulation (EEC) No 970/90 laying down detailed rules for the application in the beef and veal sector of Council Regulation (EEC) No 715/90 on the arrangements applicable to agricultural products and certain goods resulting from the processing of agricultural products originating in the African, Caribbean and Pacific States or in the overseas countries and territories and amending Regulation (EEC) No 2377/80