Quick search by citation:

25 U.S. Code § 391a - Sale for town site; removal of restriction

For the purpose of allowing any Indian allottee to sell for townsite purposes any portion of the lands allotted to him, the Secretary of the Interior may, by order, remove restrictions upon the alienation of such lands and issue fee-simple patents therefor under such rules and regulations as he may prescribe.

(June 21, 1906, ch. 3504, 34 Stat. 373.)