V. K. Maslyuchenko and O. I. Filipchuk, “Discontinuity points of separately continuous mappings with at most countable set of values”, Ukr. Mat. Zhurn., vol. 71, no. 6, pp. 801–807, Jun. 2019, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/1477