%0 Journal Article
%A Castro, Alfonso
%A Cossio, Jorge
%A Neuberger, John M.
%T A minimax principle, index of the critical point, and existence of sign-changing solutions to elliptic boundary value problems
%J Electronic Journal of Differential Equations
%D 1998
%V 1998
%I mathdoc
%U http://geodesic.mathdoc.fr/item/EJDE_1998__1998__a13/
%G en
%F EJDE_1998__1998__a13