Karlova, O. O., and V. V. Mykhailyuk. “Cross Topology and Lebesgue Triples”. Ukrains’kyi Matematychnyi Zhurnal 65, no. 5 (May 25, 2013): 722–727. Accessed April 19, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2456.