Siang Lee, Yong, and Farid E Mohamed Ghazali. “Drainage-Related Risks for Operation and Maintenance of Tunnelling Projects: An Overview”. International Journal of Engineering & Technology 7, no. 3.9 (July 9, 2018): 62–64. Accessed May 3, 2024. https://www.sciencepubco.com/index.php/ijet/article/view/15276.