Wen Kam Leong, Alex Lung Keat Ngo, Alvin Choon Hsien Wong, Jen Hua Ling, and How Teck Sia. “The Mandatory 4 Years Desludging Frequency of Underground Septic Tanks in Residential Areas: A Case Study in Sibu Sarawak, East Malaysia”. Journal of the Civil Engineering Forum 8, no. 2 (May 25, 2022): 147-156. Accessed July 18, 2024. https://journal.ugm.ac.id/v3/JCEF/article/view/3812.