Kofanov V. Boyanov–Naidenov problem and the Kolmogorov-type inequalities for functions on the real axis. Ukr. Mat. Zhurn. [Internet]. 2025 Oct. 31 [cited 2025 Dec. 5];77(1):14-27. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/8538