Não informado. (1961). Society of Petroleum Engineers Journal. Society of Petroleum Engineers.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Society of Petroleum Engineers Journal. Dallas, Tex: Society of Petroleum Engineers, 1961.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Society of Petroleum Engineers Journal. Society of Petroleum Engineers, 1961.
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