Frank, H. J. (1966). Crude oil prices in the Middle East: A study in oligopolistic price behavior. Praeger.
Lua i Stíl Chicago (17ú heag.)Frank, Helmut Jack. Crude Oil Prices in the Middle East: A Study in Oligopolistic Price Behavior. New York: Praeger, 1966.
Lua MLA (9ú heag.)Frank, Helmut Jack. Crude Oil Prices in the Middle East: A Study in Oligopolistic Price Behavior. Praeger, 1966.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.