Section
20a, act June 15, 1940, ch. 367,
54 Stat. 398, provided exemption from section
20 of this title for contracts, etc., concerning national-forest lands.
Section
20b, act Nov. 28, 1943, ch. 328,
57 Stat. 592, provided exemption from section
20 of this title for contracts, etc., concerning use of lands or water under jurisdiction of Department of the Interior.