Novikov, O.O., Rovenska, O.G. and Kozachenko, Y.A. 2018. Approximation of classes of Poisson integrals by Fejer sums. Visnyk of V. N. Karazin Kharkiv National University. Ser. Mathematics, Applied Mathematics and Mechanics. 87, (Feb. 2018), 4-12. DOI:https://doi.org/10.26565/2221-5646-2018-87-01.