Abdullayev F. G. and Kharkevych Y. I. (2020) “Approximation of the classes $C^{\psi}_{\beta}H^{\alpha}$ by biharmonic Poisson integrals”, Ukrains’kyi Matematychnyi Zhurnal, 72(1), pp. 20-35. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/1007 (Accessed: 27July2024).