Fedunyk-Yaremchuk, O.V., et al. “Approximative Characteristics of the Nikol’skii-Besov-Type Classes of Periodic Functions in the Space $B_{\infty,1}$”. Carpathian Mathematical Publications, vol. 12, no. 2, Dec. 2020, pp. 376-91, doi:10.15330/cmp.12.2.376-391.