FREE MOVEMENT OF GOODS - QUANTITATIVE RESTRICTIONS - MEASURES HAVING EQUIVALENT EFFECT - PRICE RULES - RETAIL SELLING PRICES OF PIGMEAT AND BEEF AND VEAL - FIXING OF A GROSS PROFIT MARGIN - INCORPORATION OF IMPORT AND SUPPLY COSTS - NOT PERMISSIBLE - INCOMPATIBILITY WITH THE PROVISIONS OF THE COMMON ORGANIZATIONS OF THE MARKETS - INCORPORATION OF MARKETING COSTS - PERMISSIBILITY - CONDITIONS ( EEC TREATY , ART . 30 ; REGULATIONS OF THE COUNCIL NO 121/67 , ART . 19 , AND NO 805/68 , ART . 22 )