KalchukI. V. and KharkevychY. I. (2016) “I. Approximative properties of biharmonic Poisson integrals in the classes $W^r_{\beta} H^{\alpha}$”, Ukrains’kyi Matematychnyi Zhurnal, 68(11), pp. 1493-1504. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/1936 (Accessed: 27July2024).