Sampson, A. (1975). Seven Sisters: The great oil companies and the world they shaped. Bantam Book.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रSampson, Anthony. Seven Sisters: The Great Oil Companies and the World They Shaped. USA: Bantam Book, 1975.
एमएलए (9वां संस्करण) प्रशस्ति पत्रSampson, Anthony. Seven Sisters: The Great Oil Companies and the World They Shaped. Bantam Book, 1975.
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