Dyfyniad APA

Independent Petroleum Association of America. (1971). Petroleum independent. Independent Petroleum Association of America].

Dyfyniad Arddull Chicago

Independent Petroleum Association of America. Petroleum Independent. [Tulsa, Okla.: Independent Petroleum Association of America], 1971.

Dyfyniad MLA

Independent Petroleum Association of America. Petroleum Independent. Independent Petroleum Association of America], 1971.

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