Gaya APA

Mexico, W, P, C. (1968). Seventh world petroleum congress. Vol. 1A Proceedings (1968). : England : Elsevier Publ Co Ltd.,.

Gaya MLA

Mexico, World, Petroleum, Cong. "Seventh world petroleum congress. Vol. 1A Proceedings". 1968 : England : Elsevier Publ Co Ltd.,, 1968. Text.