25 U.S. Code § 11 - Employee or employees to sign approval of tribal deeds
The Secretary of the Interior is authorized to designate an employee or employees of the Department of the Interior to sign, under the direction of the Secretary, in his name and for him, his approval of tribal deeds to allottees, to purchasers of town lots, to purchasers of unallotted lands, to persons, corporations, or organizations for lands reserved to them under the law for their use and benefit, and to any tribal deeds made and executed according to law for any of the Five Civilized Tribes of Indians in Oklahoma.
For transfer of functions of other officers, employees, and agencies of Department of the Interior, with certain exceptions, to Secretary of the Interior, with power to delegate, see Reorg. Plan No. 3 of 1950, §§ 1, 2, eff. May 24, 1950, 15 F.R. 3174,64 Stat. 1262, set out in the Appendix to Title 5, Government Organization and Employees.