Palaniandy, Samayamutthirian, Khairul Nizar Ismail, and Khairun Azizi Mohd Azizli. 2002. “Physical and Chemical Characterization of Silica Based Raw Materials from Industrial Waste”. Malaysian Journal of Science 21 (December):161-64. https://jupidi.um.edu.my/index.php/MJS/article/view/8881.