Karlova, O. O., and V. V. Mykhailyuk. “Functions of the First Baire Class With Values in Metrizable Spaces”. Ukrains’kyi Matematychnyi Zhurnal 58, no. 4 (April 25, 2006): 568–572. Accessed March 28, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3475.