Perestyuk, N. A., and O. S. Chernikova. “On Stability of Integral Sets of Impulsive Differential Systems”. Ukrains’kyi Matematychnyi Zhurnal 54, no. 2 (February 25, 2002): 249–257. Accessed December 5, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/4060.