Tan, M., S. Chong, T. Tang, A. Shukor, V. Sakthivelu, T. Ma, and M. Md Nawawi. “Tracking Control of Vertical Pneumatic Artificial Muscle System Using PID”. Journal of Telecommunication, Electronic and Computer Engineering (JTEC), vol. 8, no. 7, Oct. 2016, pp. 129-32, https://jtec.utem.edu.my/jtec/article/view/1293.