Pham, Van Viet, and Tuan Vu. “On the Asymptotic Behavior of Solutions of Differential Systems”. Ukrains’kyi Matematychnyi Zhurnal 57, no. 1 (January 25, 2005): 137–142. Accessed May 28, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3581.