United States. Bureau of the Census. (1990). U.S. exports. U.S. Dept. of Commerce, Bureau of the Census : For sale by the Supt. of Docs., U.S. G.P.O..
Lua i Stíl Chicago (17ú heag.)United States. Bureau of the Census. U.S. Exports. Washington, DC: U.S. Dept. of Commerce, Bureau of the Census : For sale by the Supt. of Docs., U.S. G.P.O., 1990.
Lua MLA (8ú heag.)United States. Bureau of the Census. U.S. Exports. U.S. Dept. of Commerce, Bureau of the Census : For sale by the Supt. of Docs., U.S. G.P.O., 1990.
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