Afanas'eva, E. S. “On the Boundary Behavior of One Class of Mappings in Metric Spaces”. Ukrains’kyi Matematychnyi Zhurnal 66, no. 1 (January 25, 2014): 17–29. Accessed April 14, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/2107.