APA

United States, . (1980). 1977 economic census of outlying areas: retail trade, wholesale trade, selected service industries, Puerto Rico geographic area statistics. Washington: Dept. of Commerce, Bureau of the Census : for sale by the Supt. of Docs., U.S. Govt. Print. Off.

Chicago

United States, . 1980. 1977 economic census of outlying areas: retail trade, wholesale trade, selected service industries, Puerto Rico geographic area statistics. Washington: Dept. of Commerce, Bureau of the Census : for sale by the Supt. of Docs., U.S. Govt. Print. Off.

Harvard

United States, . (1980). 1977 economic census of outlying areas: retail trade, wholesale trade, selected service industries, Puerto Rico geographic area statistics. Washington: Dept. of Commerce, Bureau of the Census : for sale by the Supt. of Docs., U.S. Govt. Print. Off.

MLA

United States, . 1977 economic census of outlying areas: retail trade, wholesale trade, selected service industries, Puerto Rico geographic area statistics. Washington: Dept. of Commerce, Bureau of the Census : for sale by the Supt. of Docs., U.S. Govt. Print. Off. 1980.