Generic properties of von Kármán equations Pavol Quittner (1982) Commentationes Mathematicae Universitatis Carolinae
Global bifurcation from the Fučik spectrum Walter Dambrosio (2000) Rendiconti del Seminario Matematico della Università di Padova
Global Several-Parameter Bifurcation and Continuation Theorems: a UnifiedApproach Via Complementing Maps. P.M. Fitzpatrick, I. Massabò, J. Pejsachowicz (1983) Mathematische Annalen