Extension Theorems on Weighted Sobolev Spaces Seng-Kee Chua Indiana University Mathematics Journal 1992 text pdf 10.1512/iumj.1992.41.41053 10.1512/iumj.1992.41.41053 en Indiana Univ. Math. J. 41 (1992) 1027 - 1076 state-of-the-art mathematics http://iumj.org/access/