Dyfyniad APA

Organization of Petroleum Exporting Countries. OPEC bulletin. Organization of the Petroleum Exporting Countries.

Dyfyniad Arddull Chicago

Organization of Petroleum Exporting Countries. OPEC Bulletin. Vienna, Austria: Organization of the Petroleum Exporting Countries.

Dyfyniad MLA

Organization of Petroleum Exporting Countries. OPEC Bulletin. Organization of the Petroleum Exporting Countries.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.