Dorgham, A., M. Hammi, and M. A. Hammami. “Asymptotic Behavior of a Class of Perturbed Differential Equations”. Ukrains’kyi Matematychnyi Zhurnal 73, no. 5 (May 24, 2021): 627 - 639. Accessed April 20, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/232.