Não informado. (1973). Journal of research of the United States Geological Survey. U.S. Geological Survey.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Journal of Research of the United States Geological Survey. Washington: U.S. Geological Survey, 1973.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Journal of Research of the United States Geological Survey. U.S. Geological Survey, 1973.
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