Maslyuchenko, V. K., and O. I. Filipchuk. “Discontinuity Points of Separately Continuous Mappings With at Most Countable Set of Values”. Ukrains’kyi Matematychnyi Zhurnal 71, no. 6 (June 25, 2019): 801–807. Accessed December 5, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/1477.