Abdal-Kadhim, A. M., K. Swee Leong, and N. Mohamad. “Application of Piezoelectric Energy Harvesting in Powering Radio Frequency (RF) Module”. Journal of Telecommunication, Electronic and Computer Engineering (JTEC), vol. 8, no. 4, July 2016, pp. 77-79, https://jtec.utem.edu.my/jtec/article/view/1176.