ZERNOV, A. E.; KUZINA, Yu. V. Asymptotic Behavior of Solutions of the Cauchy Problem x′ = f(t, x, x′), x(0) = 0. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 54, n. 12, p. 1698–1703, 2002. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4209. Acesso em: 6 dec. 2025.