ebrary, Inc, Leith, J. A., Price, R. A., & Spencer, J. H. (1995). Planet earth: Problems and prospects. McGill-Queen's University Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रebrary, Inc, James A. Leith, Raymond A. Price, और John H. Spencer. Planet Earth: Problems and Prospects. Montreal ; Buffalo: McGill-Queen's University Press, 1995.
एमएलए (9वां संस्करण) प्रशस्ति पत्रebrary, Inc, et al. Planet Earth: Problems and Prospects. McGill-Queen's University Press, 1995.
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