KofanovV. A. (1993) “Massiveness of the sets of extremal functions in some problems in approximation theory”, Ukrains’kyi Matematychnyi Zhurnal, 45(10), pp. 1356–1361. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/5940 (Accessed: 24November2024).