Siti Zarina Mohd Muji and Zarina Tukiran, ELECTRICAL & ELECTRONIC ENGINEERING: THEORY AND APPLICATIONS SERIES 2: ULTRASONIC AND APPLICATION. Penerbit UTHM, 2015. Accessed: Mar. 12, 2026. [Online]. Available: https://publisher.uthm.edu.my/omp/index.php/penerbituthm/catalog/book/143