Não informado. (1931). Cotton situation. U.S. Department of Agriculture, Bureau of Agricultural Economics.
Lua i Stíl Chicago (17ú heag.)Não informado. Cotton Situation. Washington: U.S. Department of Agriculture, Bureau of Agricultural Economics, 1931.
Lua MLA (8ú heag.)Não informado. Cotton Situation. U.S. Department of Agriculture, Bureau of Agricultural Economics, 1931.
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