Rosli, M. A., Z. Daud, H. Awang, N. A. Ab Aziz, M. B. Ridzuan, M. H. Abubakar, M. S. Adnan, and H. A. Tajarudin. “Adsorption Efficiency and Isotherms of COD and Color Using Limestone and Zeolite Adsorbents”. International Journal of Integrated Engineering, Vol. 10, no. 8, Dec. 2018, https://publisher.uthm.edu.my/ojs/index.php/ijie/article/view/2358.