1.
Hrabova U, Kal’chuk I. Approximation of the classes $W^{r}_{\beta,\infty}$ by three-harmonic Poisson integrals. Carpathian Math. Publ. [Internet]. 2019 Dec. 31 [cited 2024 Apr. 19];11(2):321-34. Available from: https://journals.pnu.edu.ua/index.php/cmp/article/view/2111