Ab. Wahab, Abas, Rosbi Mamat, and Syariful Syafiq Shamsudin. “The Effectiveness of Pole Placement Method in Control System Design for an Autonomous Helicopter Model in Hovering Flight”. International Journal of Integrated Engineering 1, no. 3 (1). Accessed November 27, 2020. https://publisher.uthm.edu.my/ojs/index.php/ijie/article/view/97.