OPINION - AG - ** MORTGAGE REGISTRATION TAX - INDIAN CREDIT TAX ** MORTGAGES UPON REAL PROPERTY EXECUTED TO THE INDIAN CREDIT ASSOCIATION, WHEN TENDERED FOR FILING AND RECORDING, 'ARE' SUBJECT TO THE MORTGAGE REGISTRATION TAX PROVIDED FOR IN 68 O.S. 1901 [68-1901] - 68 O.S. 1909 [68-1909] (EXEMPTION, FEDERAL) CITE: ARTICLE X, SECTION 6,25 U.S.C.A. 461, 25 U.S.C.A. 486, 25 U.S.C.A. 501,25 U.S.C.A. 510, OPINION NO. 63-514, OPINION NO. 66-207 (TODD MARKUM)