Não informado. (1938). Bimonthly Bulletin of the North Dakota Agricultural Experiment Station. North Dakota Agricultural Experiment Station.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Bimonthly Bulletin of the North Dakota Agricultural Experiment Station. Fargo, ND: North Dakota Agricultural Experiment Station, 1938.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Bimonthly Bulletin of the North Dakota Agricultural Experiment Station. North Dakota Agricultural Experiment Station, 1938.
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