Não informado. (2011). U.S. Geological Survey Bulletin. U.S. Department of the Interior, Geological Survey.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. U.S. Geological Survey Bulletin. Washington: U.S. Department of the Interior, Geological Survey, 2011.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. U.S. Geological Survey Bulletin. U.S. Department of the Interior, Geological Survey, 2011.
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