Organization of Petroleum Exporting Countries. OPEC bulletin. Organization of the Petroleum Exporting Countries.
Cita Chicago (17th ed.)Organization of Petroleum Exporting Countries. OPEC Bulletin. Vienna: Organization of the Petroleum Exporting Countries.
Cita MLA (9th ed.)Organization of Petroleum Exporting Countries. OPEC Bulletin. Organization of the Petroleum Exporting Countries.
Atenció: Aquestes cites poden no estar 100% correctes.