Zhyhallo, T. V. and Kharkevych, Y. I. (2008) “Approximation of functions from the class $\hat{C}^{\psi}_{\beta, \infty}$ by Poisson biharmonic operators in the uniform metric”, Ukrains’kyi Matematychnyi Zhurnal, 60(5), pp. 669 -. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/3185 (Accessed: 4May2024).