Nguyen Hoang Viet, Nguyen Thuy Duong, Nguyen Thanh Trung, and Nguyen Hong Thai. 2020. “Design of Internal Non-Circular Gear- Train With Improved Cycloid Profile”. Journal of Technical Education Science 15 (6):85-93. https://www.jte.edu.vn/index.php/jte/article/view/31.