Não informado. (1914). Bulletin of the Minnesota Geological Survey. University of Minnesota.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Bulletin of the Minnesota Geological Survey. Minneapolis, Minn: University of Minnesota, 1914.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Bulletin of the Minnesota Geological Survey. University of Minnesota, 1914.
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