Não informado. (1971). Petroleum Refining and Petrochemicals Literature Abstracts. American Petroleum Institute.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Petroleum Refining and Petrochemicals Literature Abstracts. New York: American Petroleum Institute, 1971.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Petroleum Refining and Petrochemicals Literature Abstracts. American Petroleum Institute, 1971.
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