[1]
A. S. Serdyuk and I. V. Sokolenko, “Linear approximation methods and the best approximations of the Poisson integrals of functions from the classes $H_{ω_p}$ in the metrics of the spaces $L_p$”, Ukr. Mat. Zhurn., vol. 62, no. 7, pp. 979–996, Jul. 2010.