APA

National Referral Center (U.S.), National Referral Center for Science and Technology (U.S.), . (1973). A directory of information resources in the United States: social sciences. Washington: Library of Congress; [for sale by the Supt. of Docs., U.S. Govt. Print. Off.].

Chicago

National Referral Center (U.S.), National Referral Center for Science and Technology (U.S.), . 1973. A directory of information resources in the United States: social sciences. Washington: Library of Congress; [for sale by the Supt. of Docs., U.S. Govt. Print. Off.].

Harvard

National Referral Center (U.S.), National Referral Center for Science and Technology (U.S.), . (1973). A directory of information resources in the United States: social sciences. Washington: Library of Congress; [for sale by the Supt. of Docs., U.S. Govt. Print. Off.].

MLA

National Referral Center (U.S.), National Referral Center for Science and Technology (U.S.), . A directory of information resources in the United States: social sciences. Washington: Library of Congress; [for sale by the Supt. of Docs., U.S. Govt. Print. Off.]. 1973.