HEMBARS'KA, S. B.; ZHYHALLO, K. M. Approximative properties of biharmonic Poisson integrals on Hölder classes. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 69, n. 7, p. 925–932, 2017. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/1746. Acesso em: 14 apr. 2025.