Não informado. (1958). North Dakota Farm Research. North Dakota Agricultural Experiment Station.
Chicago-referens (17:e uppl.)Não informado. North Dakota Farm Research. Fargo, ND: North Dakota Agricultural Experiment Station, 1958.
MLA-referens (8:e uppl.)Não informado. North Dakota Farm Research. North Dakota Agricultural Experiment Station, 1958.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.