Não informado. (2000). Experiment station record. U.S. Department of Agriculture.
Chicago-referens (17:e uppl.)Não informado. Experiment Station Record. Washington: U.S. Department of Agriculture, 2000.
MLA-referens (8:e uppl.)Não informado. Experiment Station Record. U.S. Department of Agriculture, 2000.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.