OPINION — AG — ** LAND OFFICE COMMISSIONERS — BONDS ** UNDER THE PROVISIONS OF ARTICLE XI, SECTION 6 OKLAHOMA CONSTITUTION, AND 64 Ohio St. 51 [64-51], THE COMMISSIONERS OF THE LAND OFFICE MAY EXCHANGE UNITED STATES TREASURY BONDS, IN WHICH THEY HAVE INVESTED, FOR GOVERNMENT NATIONAL MORTGAGE ASSOCIATION PARTICIPATION CERTIFICATES HAVING THE SAME MATURITY VALUE AND A HIGHER ANNUAL YIELD. (BONDS, INVESTMENTS, COMMON SCHOOL, FUNDS, APPROVAL) CITE: ARTICLE XI, SECTION 6, OPINION NO. 73-277, 64 Ohio St. 51 [64-51] (MIKE D. MARTIN)