Mohd Azwan Abdullah, Alfian Noor Firdaus, et al. “Enhancement of Cement Sand Brick Incorporating Spent Catalyst and Copper Slag As Sustainable Partial Sand Replacements”. International Journal of Integrated Engineering, vol. 17, no. 3, Sept. 2025, pp. 251-65, https://publisher.uthm.edu.my/ojs/index.php/ijie/article/view/20694.