KofanovV. A. “On the Set of Extremal Functions in Certain Kolmogorov-Type Inequalities”. Ukrains’kyi Matematychnyi Zhurnal 56, no. 8 (August 25, 2004): 1062–1075. Accessed November 22, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3822.