TSYLIN, I. V. On the Smoothness of Solutions to Elliptic Equations in Domains with Hölder Boundary. Eurasian Mathematical Journal, [S. l.], v. 6, n. 3, p. 76–92, 2015. Disponível em: https://emj.enu.kz/index.php/main/article/view/617. Acesso em: 31 oct. 2025.