Wan Ibrahim, Mohd Haziman, et al. “Compressive and Flexural Strength of Concrete Containing Palm Oil Biomass Clinker With Hooked-End Steel Fibers”. International Journal of Integrated Engineering, vol. 10, no. 9, Jan. 2019, https://penerbit.uthm.edu.my/ojs/index.php/ijie/article/view/2559.