OPINION — AG — THE AG HAS BEEN UNABLE TO LOCATE ANY STATE OR FEDERAL CONSTITUTIONAL PROVISIONS WHICH 68 O.S. 1963 Supp., 5-528 [68-5-528] (MOTOR FUEL TAX CODE) VIOLATES. IN THE ABSENCE OF SUCH PROVISION, AND UNDER THE PRESUMPTION OF VALIDITY THAT ATTENDS ALL LEGISLATIVE ENACTMENTS, THE AG IS OF THE OPINION THAT SECTION 5-528 IS CONSTITUTION. (FRED HANSEN)