Não informado. (1999). Minnesota botanical studies. Geological and Natural History Survey of Minnesota.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Minnesota Botanical Studies. Minneapolis, Minn: Geological and Natural History Survey of Minnesota, 1999.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Minnesota Botanical Studies. Geological and Natural History Survey of Minnesota, 1999.
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