Medina, Rigoberto. “Asymptotic Behavior of the Solution of a Nonlinear Differential Equation”. CUBO, A Mathematical Journal, no. 6 (July 1, 1990): 01–12. Accessed May 14, 2024. https://www.perspectivasdelacomunicacion.cl/ojs/index.php/cubo/article/view/1833.