Fatimah, Is, Narsito Narsito, and Karna Wijaya. 2013. “Effect of Aluminium Content in Aluminium Pillared Montmorillonite on Its Surface Acidity Properties”. Journal of Mathematical and Fundamental Sciences 43 (2):123-38. https://doi.org/10.5614/itbj.sci.2011.43.2.5.