Powell. Retention and Resistance. Utah State University Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रPowell. Retention and Resistance. Utah State University Press.
एमएलए (9वां संस्करण) प्रशस्ति पत्रPowell. Retention and Resistance. Utah State University Press.
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