Huynh VQ. Application of the modified Euler-Lagrange equation to multi-degree-of-freedom problems. Tạp chí Khoa học Công nghệ Giao Thông Vận Tải [Internet]. 2025 Feb. 19 [cited 2026 Aug. 14];14(1):11-20. Available from: https://tapchi.ut.edu.vn/index.php/jtst/article/view/336