APA

United States, . (1970). The environmental decade (action proposals for the 1970's): Hearings, Ninety-first Congress, second session. Washington: U.S. Govt. Print. Off.

Chicago

United States, . 1970. The environmental decade (action proposals for the 1970's): Hearings, Ninety-first Congress, second session. Washington: U.S. Govt. Print. Off.

Harvard

United States, . (1970). The environmental decade (action proposals for the 1970's): Hearings, Ninety-first Congress, second session. Washington: U.S. Govt. Print. Off.

MLA

United States, . The environmental decade (action proposals for the 1970's): Hearings, Ninety-first Congress, second session. Washington: U.S. Govt. Print. Off. 1970.