Hentschel. Security in the Bubble. University of Minnesota Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रHentschel. Security in the Bubble. University of Minnesota Press.
एमएलए (9वां संस्करण) प्रशस्ति पत्रHentschel. Security in the Bubble. University of Minnesota Press.
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