Não informado. (2017). Petroleum Engineer. Petroleum Engineer Publications.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Petroleum Engineer. Dallas, Tex: Petroleum Engineer Publications, 2017.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Petroleum Engineer. Petroleum Engineer Publications, 2017.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.