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..
芝加哥风格引文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.
MLA引文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.
警告：这些引文格式不一定是100％准确.