Não informado. (1938). Bimonthly Bulletin of the North Dakota Agricultural Experiment Station. North Dakota Agricultural Experiment Station.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Bimonthly Bulletin of the North Dakota Agricultural Experiment Station. Fargo, ND: North Dakota Agricultural Experiment Station, 1938.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Bimonthly Bulletin of the North Dakota Agricultural Experiment Station. North Dakota Agricultural Experiment Station, 1938.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.