Gue, I. H. V., and A. Y. Chua. “Development of a Fuzzy GS-PID Controlled Quadrotor for Payload Drop Missions”. Journal of Telecommunication, Electronic and Computer Engineering (JTEC), vol. 10, no. 1-5, Feb. 2018, pp. 55-58, https://jtec.utem.edu.my/jtec/article/view/3626.