26 U.S. Code § 6064. Signature presumed authentic

The fact that an individual’s name is signed to a return, statement, or other document shall be prima facie evidence for all purposes that the return, statement, or other document was actually signed by him.

(Aug. 16, 1954, ch. 736, 68A Stat. 749.)

Title 27: Alcohol, Tobacco Products and Firearms