Lang, W. L. (1991). Centennial West: Essays on the Northern Tier states. University of Washington Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रLang, William L. Centennial West: Essays on the Northern Tier States. Seattle: University of Washington Press, 1991.
एमएलए (8वां संस्करण) प्रशस्ति पत्रLang, William L. Centennial West: Essays on the Northern Tier States. University of Washington Press, 1991.
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