25 U.S. Code § 694 - Personal property rights; restrictions
Upon publication in the Federal Register of the final roll as provided in section 693 of this title, the rights or beneficial interests in tribal property of each person whose name appears on the roll shall constitute personal property which may be inherited or bequeathed, but shall not otherwise be subject to alienation or encumbrance before the transfer of title to such tribal property as provided in section 695 of this title without the approval of the Secretary. Any contract made in violation of this section shall be null and void.
Source(Aug. 13, 1954, ch. 733, § 4,68 Stat. 725.)