KHOSRAVAN, M., S.J. FATEMI, and A.S. SALJOOGHI. 2010. “Synthesis, Characterization and Adsorption of Metal Ions on New Silica-Gel Organofunctionalized Compound”. Asian Journal of Chemistry 19 (2):1131-36. https://asianpubs.org/index.php/ajchem/article/view/20181.