Indra, Win Adiyansyah, and Muhamad Shafiq Adam Mohd Shariff. “Message Conveyor by Motion for Paralyze People Powered Using RF Energy Harvesting”. International Journal of Integrated Engineering, vol. 12, no. 8, Aug. 2020, pp. 233-9, https://publisher.uthm.edu.my/ojs/index.php/ijie/article/view/5712.