Não informado. (1936). Agricultural Statistics. U.S. Department of Agriculture.
Chicago-referens (17:e uppl.)Não informado. Agricultural Statistics. Washington: U.S. Department of Agriculture, 1936.
MLA-referens (8:e uppl.)Não informado. Agricultural Statistics. U.S. Department of Agriculture, 1936.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.