APA

United States, . (1981). 1977 economic censuses of outlying areas: manufactures, Puerto Rico. [Washington, D.C.?]: U.S. Dept. of Commerce, Bureau of the Census.

Chicago

United States, . 1981. 1977 economic censuses of outlying areas: manufactures, Puerto Rico. [Washington, D.C.?]: U.S. Dept. of Commerce, Bureau of the Census.

Harvard

United States, . (1981). 1977 economic censuses of outlying areas: manufactures, Puerto Rico. [Washington, D.C.?]: U.S. Dept. of Commerce, Bureau of the Census.

MLA

United States, . 1977 economic censuses of outlying areas: manufactures, Puerto Rico. [Washington, D.C.?]: U.S. Dept. of Commerce, Bureau of the Census. 1981.