Vasileva, Nikolina. “Stability of Steady-State Motions of Systems of Symmetric Rigid Bodies With Ball-and-Socket Joints”. Ann. Sofia Univ. Fac. Math. and Inf. 87 (December 12, 1995): 337–349. Accessed November 21, 2024. https://ftl5.uni-sofia.bg/index.php/fmi/article/view/426.