Positive Solutions of \Delta_g u = u^q + Su Singular at Submanifolds with Boundary David Finn Indiana University Mathematics Journal 1994 text pdf 10.1512/iumj.1994.43.43060 10.1512/iumj.1994.43.43060 en Indiana Univ. Math. J. 43 (1994) 1359 - 1397 state-of-the-art mathematics http://iumj.org/access/