PAULO M. GUZMAN; JUAN E. NAPOLES VALDES; LUCIANO M. LUGO. On the Boundedness of Some Nonlinear Differential Equation of Second Order. International Journal of Mathematics And its Applications, [S. l.], v. 3, n. 4 - E, p. 23–31, 2015. Disponível em: http://ijmaa.in/index.php/ijmaa/article/view/522. Acesso em: 19 may. 2024.