Nguyen, T. L., M. D. Duong, and T. H. Do. “A Direct Lyapunov-Backstepping Approach for Stabilizing Gantry Systems With Flexible Cable”. Proceedings of Engineering and Technology Innovation, vol. 8, Apr. 2018, pp. 15-22, https://ojs.imeti.org/index.php/PETI/article/view/1734.