PerestyukN. A., and ChernikovaO. S. “On the Stability of Invariant Sets of Discontinuous Dynamical Systems”. Ukrains’kyi Matematychnyi Zhurnal 53, no. 1 (January 25, 2001): 78-84. Accessed November 22, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/4223.