Urmanchev VI. Qualitative Investigation of Discontinuous Dynamical Systems on a Plane by the Method of Pointwise Mappings. Ukr. Mat. Zhurn. [Internet]. 2004 Jan. 25 [cited 2025 Apr. 13];56(1):108-1. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/3732