Não informado. (2007). Report of the Iowa Agricultural Experiment Station for de two years. Agricultural Experiment Station.
Chicago-referens (17:e uppl.)Não informado. Report of the Iowa Agricultural Experiment Station for De Two Years. Ames, Iowa: Agricultural Experiment Station, 2007.
MLA-referens (8:e uppl.)Não informado. Report of the Iowa Agricultural Experiment Station for De Two Years. Agricultural Experiment Station, 2007.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.