APA

United States, . (1969). National Science Research Data Processing and Information Retrieval System: Hearings, Ninety-first Congress, first session, on H.R. 8809 ... April 29 and 30, 1969. Washington: U.S. Govt. Print. Off.

Chicago

United States, . 1969. National Science Research Data Processing and Information Retrieval System: Hearings, Ninety-first Congress, first session, on H.R. 8809 ... April 29 and 30, 1969. Washington: U.S. Govt. Print. Off.

Harvard

United States, . (1969). National Science Research Data Processing and Information Retrieval System: Hearings, Ninety-first Congress, first session, on H.R. 8809 ... April 29 and 30, 1969. Washington: U.S. Govt. Print. Off.

MLA

United States, . National Science Research Data Processing and Information Retrieval System: Hearings, Ninety-first Congress, first session, on H.R. 8809 ... April 29 and 30, 1969. Washington: U.S. Govt. Print. Off. 1969.