Ellen, R. (1982). Environment, subsistence, and system: The ecology of small-scale social formations. Cambridge University Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रEllen, Roy. Environment, Subsistence, and System: The Ecology of Small-scale Social Formations. [Cambridge [Cambridgeshire ; New York: Cambridge University Press, 1982.
एमएलए (9वां संस्करण) प्रशस्ति पत्रEllen, Roy. Environment, Subsistence, and System: The Ecology of Small-scale Social Formations. Cambridge University Press, 1982.
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