1 . QUESTIONS FOR A PRELIMINARY RULING - REFERENCE TO THE COURT - STAGE OF THE PROCEEDINGS AT WHICH REFERENCE SHOULD BE MADE - APPRAISAL BY THE NATIONAL COURT ( EEC TREATY , ART . 177 ) 2 . FREE MOVEMENT OF GOODS - QUANTITATIVE RESTRICTIONS - MEASURES HAVING EQUIVALENT EFFECT - CONCEPT ( EEC TREATY , ART . 30 ) 3 . COMPETITION - UNDERTAKINGS ENTRUSTED WITH THE OPERATION OF SERVICES OF GENERAL ECONOMIC INTEREST - SUBJECT TO THE TREATY RULES - PROTECTION ENSURED BY MEASURES RESTRICTING IMPORTS FROM OTHER MEMBER STATES - NOT ACCEPTABLE ( EEC TREATY , ARTS 30 AND 90 ( 2 )) 4 . FREE MOVEMENT OF GOODS - QUANTITATIVE RESTRICTIONS - MEASURES HAVING EQUIVALENT EFFECT - SUPPLIES OF PETROLEUM PRODUCTS - OBLIGATION TO PURCHASE FROM A NATIONAL REFINERY ( EEC TREATY , ART . 30 ) 5 . FREE MOVEMENT OF GOODS - DEROGATIONS - ARTICLE 36 OF THE TREATY - COMMUNITY RULES FOR THE PROTECTION OF THE SAME INTERESTS - EFFECTS ( EEC TREATY , ART . 36 ) 6 . FREE MOVEMENT OF GOODS - DEROGATIONS - ARTICLE 36 OF THE TREATY - PURPOSE - SCOPE - UNNECESSARY OR DISPROPORTIONATE MEASURES - NOT ACCEPTABLE ( EEC TREATY , ART . 36 ) 7 . FREE MOVEMENT OF GOODS - DEROGATIONS - PUBLIC SECURITY - SUPPLIES OF PETROLEUM PRODUCTS - OBJECTIVE COVERED BY THE CONCEPT OF PUBLIC SECURITY - ADOPTION OF APPROPRIATE RULES - RULES MAKING IT POSSIBLE TO ACHIEVE OTHER OBJECTIVES OF AN ECONOMIC NATURE - ACCEPTABLE ( EEC TREATY , ART . 36 ) 8 . FREE MOVEMENT OF GOODS - DEROGATIONS - PUBLIC SECURITY - SUPPLIES OF PETROLEUM PRODUCTS - OBLIGATION TO PURCHASE FROM A NATIONAL REFINERY - ACCEPTABLE - CONDITIONS AND LIMITS ( EEC TREATY , ART . 36 )