APA

United States, . (1972). Projections and educational statistics to 1980-81. Washington, D.C: Government Printing Office.

Chicago

United States, . 1972. Projections and educational statistics to 1980-81. Washington, D.C: Government Printing Office.

Harvard

United States, . (1972). Projections and educational statistics to 1980-81. Washington, D.C: Government Printing Office.

MLA

United States, . Projections and educational statistics to 1980-81. Washington, D.C: Government Printing Office. 1972.