Ahmad Hazim Bin Ahmad Firdaus, and Norashidah Abd Rahman. “Strength of Lightweight Cellular Concrete-Filled Hollow Section Added Steel Fiber”. Recent Trends in Civil Engineering and Built Environment, vol. 3, no. 1, Nov. 2021, pp. 233-40, https://publisher.uthm.edu.my/periodicals/index.php/rtcebe/article/view/3559.