Double resonance problems with respect to the Fucik spectrum Kanishka PereraMartin Schechter 35J6558E0549B27 Indiana University Mathematics Journal 2003 text pdf 10.1512/iumj.2003.52.2074 10.1512/iumj.2003.52.2074 en Indiana Univ. Math. J. 52 (2003) 1 - 18 state-of-the-art mathematics http://iumj.org/access/