Global Branches of Solutions to Nonlinear Elliptic Eigenvalue Problems Jim Cushing Indiana University Mathematics Journal 1971 text pdf 10.1512/iumj.1971.20.20099 10.1512/iumj.1971.20.20099 en Indiana Univ. Math. J. 20 (1971) 1035 - 1045 state-of-the-art mathematics http://iumj.org/access/