1. Linear Analysis: An Introduction Course;Bollobas,1999
2. Methods in Nonlinear Analysis;Chang,2005
3. Bifurcation from simple eigenvalues;Crandall;J. Funct. Anal.,1971
4. Elliptic Partial Differential Equations of Second Order;Gilbarg,2001
5. Finite Morse index solutions of exponential problems;Dancer;Ann. Inst. H. Poincaré Anal. Non Linéaire,2008