Não informado. (1939). Feed situation. U.S. Department of Agriculture, Bureau of Agricultural Economics.
Chicago-referens (17:e uppl.)Não informado. Feed Situation. Washington: U.S. Department of Agriculture, Bureau of Agricultural Economics, 1939.
MLA-referens (8:e uppl.)Não informado. Feed Situation. U.S. Department of Agriculture, Bureau of Agricultural Economics, 1939.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.