Nguyen , M. T., V. Đông H. Nguyen, P. L. Nguyen, and V. T. Le. “Modelling and Optimal Control for Two- Wheeled Self-Balancing Robot”. Journal of Technical Education Science, vol. 11, no. 3, Sept. 2016, pp. 22-30, https://www.jte.edu.vn/index.php/jte/article/view/416.