Ibrahim, Farah Nur Diyana, Zawawi Daud, Ab Aziz Abdul Latiff, Mohd Baharudin Ridzuan, Zulkifli Ahmad, Halizah Awang, and Aminaton Marto. 2017. “Ammoniacal Nitrogen and COD Removal Using Zeolite-Feldspar Mineral Composite Adsorbent”. International Journal of Integrated Engineering 8 (3). https://publisher.uthm.edu.my/ojs/index.php/ijie/article/view/1478.