Zulkifli, Batrisyia, et al. “Shear Capacity of Reinforced Concrete Beam With an Opening Retrofit Using Steel Fiber and Metakaolin”. Journal of Structural Monitoring and Built Environment, vol. 3, no. 1, Aug. 2023, pp. 6-14, https://journal.uthm.edu.my/index.php/jsmbe/article/view/14945.