Binti Mohd Ajis, Siti Humairah, et al. “Investigations on the Cross-Hole Sonic Logging Test on Bored Piles at Bridge 29 in Section 8 for East Coast Rail Link (ECRL)”. Progress in Engineering Application and Technology, vol. 4, no. 2, Dec. 2023, pp. 1245-51, https://penerbit.uthm.edu.my/periodicals/index.php/peat/article/view/12618.