CHRISTOV, O. On the perturbations of a mechanical system from the rigid body dynamics. Ann. Sofia Univ. Fac. Math. and Inf., [S. l.], v. 86, n. 2, p. 5–15, 1994. Disponível em: https://stipendii.uni-sofia.bg/index.php/fmi/article/view/503. Acesso em: 5 dec. 2024.