Borsuk, M. V., and M. I. Plesha. “Estimates of Generalized Solutions of the Dirichlet Problem for Quasilinear Elliptic Equations of the Second Order in a Domain With Conical Boundary Point”. Ukrains’kyi Matematychnyi Zhurnal, vol. 50, no. 10, Oct. 1998, pp. 1299–1309, https://umj.imath.kiev.ua/index.php/umj/article/view/4816.