Urmanchev, V. (1992) “Methods of the investigation of dynamical systems with pulse effect and ‘mortal’ dynamical systems ”, Ukrains’kyi Matematychnyi Zhurnal, 44(11), pp. 1605–1613. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/8264 (Accessed: 7 April 2025).