ÇAKMAK, D. Oscillation criteria for nonlinear second-order differential equations with damping. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 60, n. 5, p. 694–700, 2008. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3186. Acesso em: 11 apr. 2025.