25 C.F.R. § 211.29

The regulations in this part may be superseded by the provisions of any tribal constitution, bylaw or charter issued pursuant to the Indian Reorganization Act of June 18, 1934 (48 Stat. 984; 25 U.S.C. 461-479), the Alaska Act of May 1, 1936 (49 Stat. 1250; 48 U.S.C. 362,258a), or the Oklahoma Indian Welfare Act of June 26, 1936 (49 Stat. 1967; 25 U.S.C., and Sup., 501-509), or by ordinance, resolution, or other action authorized under such constitution, bylaw or charter; Provided, that such tribal law may not supersede the requirements of Federal statutes applicable to Indian mineral leases. The regulations in this part, in so far as they are not so superseded, shall apply to leases and permits made by organized tribes if the validity of the lease or permit depends upon the approval of the Secretary of the Interior.