Awal, M. R., M. Jusoh, T. Sabapathy, R. B. Ahmad, M. R. Kamarudin, M. N. Osman, M F. Ahmad, S. A. Rahman, and A. N. Dagang. “A Patternless Piezoelectric Energy Harvester for Ultra Low Frequency Applications”. International Journal of Integrated Engineering 12, no. 7 (October 26, 2020): 187–194. Accessed April 8, 2026. https://penerbit.uthm.edu.my/ojs/index.php/ijie/article/view/7271.