Abdullayev FG, Kharkevych YI. Approximation of the classes $C^{\psi}_{\beta}H^{\alpha}$ by biharmonic Poisson integrals. Ukr. Mat. Zhurn. [Internet]. 2020 Jan. 15 [cited 2025 Dec. 5];72(1):20-35. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/1007