A Review of Crude Oil Extraction Methods from Petroleum Sludge. International Journal of Engineering Technology and Sciences, [S. l.], v. 8, n. 1, p. 40–50, 2021. DOI: 10.15282/ijets.8.1.2021.1006. Disponível em: https://journal.ump.edu.my/ijets/article/view/7226. Acesso em: 4 jun. 2025.