Dyfyniad APA

(1971). Selected documents of the international petroleum industry. Vienna: Organization of the Petroleum Exporting Countries.

Dyfyniad Arddull Chicago

Selected Documents of the International Petroleum Industry. Vienna: Organization of the Petroleum Exporting Countries, 1971.

Dyfyniad MLA

Selected Documents of the International Petroleum Industry. Vienna: Organization of the Petroleum Exporting Countries, 1971.

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