Não informado. (1981). Energy progress. American Institute of Chemical Engineers.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Energy Progress. New York: American Institute of Chemical Engineers, 1981.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Energy Progress. American Institute of Chemical Engineers, 1981.
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