Não informado. (1931). Dairy situation. U.S. Department of Agriculture, Economic Research Service.
Chicago-referens (17:e uppl.)Não informado. Dairy Situation. Washington: U.S. Department of Agriculture, Economic Research Service, 1931.
MLA-referens (8:e uppl.)Não informado. Dairy Situation. U.S. Department of Agriculture, Economic Research Service, 1931.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.