APA

United States, . (1967). Nationwide system of trails: hearings, 90th Congress, 1st session, on S. 827, Mar. 15 and 16, 1967. [Washington, D.C.]: .

Chicago

United States, . 1967. Nationwide system of trails: hearings, 90th Congress, 1st session, on S. 827, Mar. 15 and 16, 1967. [Washington, D.C.]: .

Harvard

United States, . (1967). Nationwide system of trails: hearings, 90th Congress, 1st session, on S. 827, Mar. 15 and 16, 1967. [Washington, D.C.]: .

MLA

United States, . Nationwide system of trails: hearings, 90th Congress, 1st session, on S. 827, Mar. 15 and 16, 1967. [Washington, D.C.]: . 1967.