Akbarimajd, Adel, and Amir Mohamamd Hossini. “Multi-Agent Optimal Control of Ball Balancing on a Mobile”. International Journal of Integrated Engineering 7, no. 2 (December 3, 2015). Accessed March 8, 2021. https://publisher.uthm.edu.my/ojs/index.php/ijie/article/view/1146.