Pipe, J. (2015). Early people (First American edition.). DK Publishing.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रPipe, Jim. Early People. First American edition. New York, New York: DK Publishing, 2015.
एमएलए (8वां संस्करण) प्रशस्ति पत्रPipe, Jim. Early People. First American edition. DK Publishing, 2015.
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