Não informado. (1971). Environment information access. Environmental Information Center of Ecology Forum.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Environment Information Access. New York: Environmental Information Center of Ecology Forum, 1971.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Environment Information Access. Environmental Information Center of Ecology Forum, 1971.
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