1. Multiple parameter stability theory and its applications;Huseyin,1986
2. Perturbation methods, bifurcation theory, and computer algebra;Rand,1987
3. Nonlinear oscillations, dynamical systems, and bifurcations of vector fields;Guckenheimer,1993
4. Method of normal form;Nayfeh,1993
5. Normal forms and bifurcation of planar vector fields;Chow,1994