Le Thi Minh Tam, Nguyen Viet Ngu, and Pham Duc Hung. “ REINFORCEMENT LEARNING–ASSISTED PPO–PD TRAJECTORY TRACKING CONTROL FOR A 6-DOF ROBOTIC MANIPULATOR: A COMPARATIVE SIMULATION WITH FEEDFORWARD PD”. Journal of Applied Science and Technology, Vol. 49, Mar. 2026, pp. 88-94, https://jst.utehy.edu.vn/index.php/jst/article/view/855.