SOSNITSKII, S. P. On instability of conservative systems with gyroscopic forces. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 49, n. 10, p. 1422–1428, 1997. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5139. Acesso em: 6 dec. 2025.