Elliptic Boundary Value Problems with Singular Coefficients and Critical Nonlinearities Henrik Egnell Indiana University Mathematics Journal 1989 text pdf 10.1512/iumj.1989.38.38012 10.1512/iumj.1989.38.38012 en Indiana Univ. Math. J. 38 (1989) 235 - 251 state-of-the-art mathematics http://iumj.org/access/