Frank, H. J. (1966). Crude oil prices in the Middle East: A study in oligopolistic price behavior. Praeger.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रFrank, Helmut Jack. Crude Oil Prices in the Middle East: A Study in Oligopolistic Price Behavior. New York: Praeger, 1966.
एमएलए (9वां संस्करण) प्रशस्ति पत्रFrank, Helmut Jack. Crude Oil Prices in the Middle East: A Study in Oligopolistic Price Behavior. Praeger, 1966.
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