Não informado. (2017). Petroleum Engineer. Petroleum Engineer Publications.
Chicago-Zitierstil (17. Ausg.)Não informado. Petroleum Engineer. Dallas, Tex: Petroleum Engineer Publications, 2017.
MLA-Zitierstil (8. Ausg.)Não informado. Petroleum Engineer. Petroleum Engineer Publications, 2017.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.