Não informado. (2017). Petroleum Engineer. Petroleum Engineer Publications.
Chicago-referens (17:e uppl.)Não informado. Petroleum Engineer. Dallas, Tex: Petroleum Engineer Publications, 2017.
MLA-referens (8:e uppl.)Não informado. Petroleum Engineer. Petroleum Engineer Publications, 2017.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.