Sevost’yanovE. A., and SkvortsovS. A. 2018. “On Convergence of Mappings in Metric Spaces With direct and Inverse Modulus Conditions”. Ukrains’kyi Matematychnyi Zhurnal 70 (7), 952-687. https://umj.imath.kiev.ua/index.php/umj/article/view/1608.