Organization of Petroleum Exporting Countries. OPEC bulletin. Organization of the Petroleum Exporting Countries.
Chicago-Zitierstil (17. Ausg.)Organization of Petroleum Exporting Countries. OPEC Bulletin. Vienna, Austria: Organization of the Petroleum Exporting Countries.
MLA-Zitierstil (9. Ausg.)Organization of Petroleum Exporting Countries. OPEC Bulletin. Organization of the Petroleum Exporting Countries.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.