25 U.S.C. § 4307
There are authorized to be appropriated such sums as are necessary to carry out this chapter, to remain available until expended.
(Pub. L. 106–464, § 10, formerly § 8, , 114 Stat. 2018; renumbered § 10, Pub. L. 116–261, § 3(d)(1), , 134 Stat. 3308.)