SOSNITSKY, S. P. On rough instability of autonomous systems’ equilibrium . Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 40, n. 1, p. 95–101, 1987. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/9062. Acesso em: 6 dec. 2025.