44 U.S.C. § 1721
Heads of departments may exchange surplus documents for other documents and books required by them, when it is to the advantage of the public service.
(Pub. L. 90–620, , 82 Stat. 1282.)
Based on 44 U.S. Code, 1964 ed., § 93 (Jan. 12, 1895, ch. 23, § 95, 28 Stat. 623).