M.H. Muhammad Sidik, S.A. Che Ghani, R.A.R. Maarof. “Validation Test on Thresholds for Wheelchair Power-Assist System Activation Using Population Data”. International Journal of Advanced Science and Technology, Vol. 29, no. 8s, June 2020, pp. 4387-95, http://sersc.org/journals/index.php/IJAST/article/view/25480.