Urmanchev, V.I. (2004) “Qualitative Investigation of Discontinuous Dynamical Systems on a Plane by the Method of Pointwise Mappings”, Ukrains’kyi Matematychnyi Zhurnal, 56(1), pp. 108–118. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/3732 (Accessed: 14 April 2025).