Heinonen, Juha, and Pekka Koskela. “Weighted Sobolev and Poincaré Inequalities and Quasiregular Mappings of Polynomial Type”. MATHEMATICA SCANDINAVICA 77 (December 1, 1995): 251–271. Accessed April 4, 2025. https://www.mscand.dk/article/view/12564.