APA aipamena

(1979). OPEC national oil company profiles. Secretariat, Organization of the Petroleum Exporting Countries.

Chicago Style aipamena

OPEC National Oil Company Profiles. Vienna: Secretariat, Organization of the Petroleum Exporting Countries, 1979.

MLA aipamena

OPEC National Oil Company Profiles. Secretariat, Organization of the Petroleum Exporting Countries, 1979.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.