Não informado. (1926). Yearbook of agriculture. U.S. Department of Agriculture.
Chicago-referens (17:e uppl.)Não informado. Yearbook of Agriculture. Washington: U.S. Department of Agriculture, 1926.
MLA-referens (8:e uppl.)Não informado. Yearbook of Agriculture. U.S. Department of Agriculture, 1926.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.