Diffendal. Great Plains Geology. Bison Books, University of Nebraska Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रDiffendal. Great Plains Geology. Bison Books, University of Nebraska Press.
एमएलए (9वां संस्करण) प्रशस्ति पत्रDiffendal. Great Plains Geology. Bison Books, University of Nebraska Press.
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