Columbia subject headings:
Organization of Arab Petroleum Exporting Countries.
Petroleum industry and trade--Arab countries--Periodicals.
Harvard subject headings:
Organization of Arab Petroleum Exporting Countries--Periodicals.
Petroleum industry and trade--Arab countries--Periodicals.
Princeton subject headings:
Organization of Arab Petroleum Exporting Countries.
Periodicals.
Petroleum industry and trade--Arab countries--Periodicals.