S. A. Stasyuk, “Kolmogorov Widths for Analogs of the Nikol’skii–Besov Classes with Logarithmic Smoothness”, Ukr. Mat. Zhurn., vol. 67, no. 11, pp. 1579–1584, Nov. 2015, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/2092