VOSKRESENSKY , E. V. The Lyapunov direct method in the theory of asymptotic equivalence of differential equations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 43, n. 1, p. 115–118, 1991. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/9314. Acesso em: 6 dec. 2025.