Black, G. (1992). Iowa birdlife. Published for the Nature Conservancy by the University of Iowa Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रBlack, Gladys. Iowa Birdlife. Iowa City: Published for the Nature Conservancy by the University of Iowa Press, 1992.
एमएलए (9वां संस्करण) प्रशस्ति पत्रBlack, Gladys. Iowa Birdlife. Published for the Nature Conservancy by the University of Iowa Press, 1992.
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