Romanyuk, A.S. and Yanchenko, S.Y. 2021. Estimates of approximation characteristics and properties of operators of the best approximation for the classes of periodic functions in the space $B_{1,1}$. Ukrains’kyi Matematychnyi Zhurnal. 73, 8 (Aug. 2021), 1102 - 1119. DOI:https://doi.org/10.37863/umzh.v73i8.6755.