Chang Kim, Heon, Won Jae Jeong, Who Chul Lee, and Seung Kyu Park. “Demetallization by MCM-48 from Asphalten of Vacuum Residual Oils: Analysis by UV-Visible Spectrophotometer”. Asian Journal of Chemistry 27, no. 11 (July 22, 2015): 4288–4290. Accessed July 6, 2024. https://asianpubs.org/index.php/ajchem/article/view/27_11_85.