Zulkifli, N. I. ., A. . Alisibramulisi, N. . Saari, R. Hassan, E. . Shaffie, N. Mohamad Bhkari, and M. N. Muhd Sidek. “Experimental Investigation of Ultrasonic Pulse Velocity (UPV) Test Specimen in Assessing the Strength of Steel Fiber Reinforced Concrete Structure”. Journal of Advanced Industrial Technology and Application, vol. 2, no. 2, Dec. 2021, pp. 34-41, https://publisher.uthm.edu.my/ojs/index.php/jaita/article/view/10125.