APA

U.S. Census Bureau, . (1991). U.S. merchandise trade. Washington D.C: U.S. Dept. of Commerce, Bureau of the Census.

Chicago

U.S. Census Bureau, . 1991. U.S. merchandise trade. Washington D.C: U.S. Dept. of Commerce, Bureau of the Census.

Harvard

U.S. Census Bureau, . (1991). U.S. merchandise trade. Washington D.C: U.S. Dept. of Commerce, Bureau of the Census.

MLA

U.S. Census Bureau, . U.S. merchandise trade. Washington D.C: U.S. Dept. of Commerce, Bureau of the Census. 1991.