Sevost'yanov, E.A. (2009) “Generalization of one Poletskii lemma to classes of space mappings”, Ukrains’kyi Matematychnyi Zhurnal, 61(7), pp. 969–975. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/3071 (Accessed: 5 December 2025).