Viola, J. (2019). Polar bears: Survival on the ice (First edition.). First Second.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रViola, Jason. Polar Bears: Survival on the Ice. First edition. New York: First Second, 2019.
एमएलए (8वां संस्करण) प्रशस्ति पत्रViola, Jason. Polar Bears: Survival on the Ice. First edition. First Second, 2019.
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