Ligun AA, Chernaya EV. On extremal problems on classes of functions defined by integral moduli of continuity. Ukr. Mat. Zhurn. [Internet]. 1997 Nov. 25 [cited 2025 Apr. 13];49(11):1499–1503. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/5148