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), pp. 1102 - 1119. doi: 10.37863/umzh.v73i8.6755.