Não informado. (1931). Dairy situation. U.S. Department of Agriculture, Economic Research Service.
Lua i Stíl Chicago (17ú heag.)Não informado. Dairy Situation. Washington: U.S. Department of Agriculture, Economic Research Service, 1931.
Lua MLA (8ú heag.)Não informado. Dairy Situation. U.S. Department of Agriculture, Economic Research Service, 1931.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.