Chang Kim, Heon, Won Jae Jeong, Who Chul Lee, and Seung Kyu Park. 2015. “Demetallization by MCM-48 from Asphalten of Vacuum Residual Oils: Analysis by UV-Visible Spectrophotometer”. Asian Journal of Chemistry 27 (11):4288-90. https://doi.org/10.14233/ajchem.2015.19516.