Lê Thanh Hải, Nguyễn Duy Anh, and Phạm Thị Thu Hiền. “A Study on Design and Manufacturing a Supporting Mechanism for Stair Climbing Robot”. Journal of Technical Education Science, vol. 10, no. 3, Sept. 2015, pp. 30-36, https://www.jte.edu.vn/index.php/jte/article/view/607.