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”, J. civil eng. forum, vol. 8, no. 2, pp. 147-156, May 2022.