Não informado. (1923). Agriculture yearbook. U.S. Department of Agriculture.
Chicago-referens (17:e uppl.)Não informado. Agriculture Yearbook. Washington: U.S. Department of Agriculture, 1923.
MLA-referens (8:e uppl.)Não informado. Agriculture Yearbook. U.S. Department of Agriculture, 1923.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.