Tsylin, Ivan Vyacheslavovich. “On the Smoothness of Solutions to Elliptic Equations in Domains With Hölder Boundary”. Eurasian Mathematical Journal 6, no. 3 (September 30, 2015): 76–92. Accessed February 23, 2026. https://emj.enu.kz/index.php/main/article/view/617.