Frank, H. J. (1966). Crude oil prices in the Middle East: A study in oligopolistic price behavior. Praeger.
Chicago (17e ed.) BronvermeldingFrank, Helmut Jack. Crude Oil Prices in the Middle East: A Study in Oligopolistic Price Behavior. New York: Praeger, 1966.
MLA (9e ed.) BronvermeldingFrank, Helmut Jack. Crude Oil Prices in the Middle East: A Study in Oligopolistic Price Behavior. Praeger, 1966.