Vakarchuk, S. B. and Vakarchuk, M. B. (2022) “$K$-functionals and extreme problems of the theory of approximation of the classes of analytic functions in a circle. II”, *Ukrains’kyi Matematychnyi Zhurnal*, 74(7), pp. 921 - 929. doi: 10.37863/umzh.v74i7.6981.