Não informado. (2000). Agricultural library notes. U.S. Department of Agriculture.
Chicago-referens (17:e uppl.)Não informado. Agricultural Library Notes. Washington: U.S. Department of Agriculture, 2000.
MLA-referens (8:e uppl.)Não informado. Agricultural Library Notes. U.S. Department of Agriculture, 2000.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.