Gibbons. Ecoviews Too. The University of Alabama Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रGibbons. Ecoviews Too. The University of Alabama Press.
एमएलए (9वां संस्करण) प्रशस्ति पत्रGibbons. Ecoviews Too. The University of Alabama Press.
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