Gregory, G. H. (2002). Alcatraz screw: My years as a guard in America's most notorious prison. University of Missouri Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रGregory, George H. Alcatraz Screw: My Years as a Guard in America's Most Notorious Prison. Columbia, MO: University of Missouri Press, 2002.
एमएलए (9वां संस्करण) प्रशस्ति पत्रGregory, George H. Alcatraz Screw: My Years as a Guard in America's Most Notorious Prison. University of Missouri Press, 2002.
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