Hrabova UZ, Kalchuk IV, Stepanyuk TA. On the approximation of the classes $W_{β}^rH^{α}$ by biharmonic Poisson integrals. Ukr. Mat. Zhurn. [Internet]. 2018May25 [cited 2024Apr.18];70(5):625-34. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/1582