Yanchenko, S.Ya., and O.Ya. Radchenko. “Approximation Characteristics of the Isotropic Nikol’skii-Besov Functional Classes”. Carpathian Mathematical Publications 13, no. 3 (December 30, 2021): 851–861. Accessed November 21, 2024. https://journals.pnu.edu.ua/index.php/cmp/article/view/5649.