1. On degree theory for multivalued mappings and applications;Webb;Boll. Un. mat. Ital.,1974
2. Linear Operators;Dunford,1964
3. Convex Analysis and Variational Problems;Ekeland,1976
4. An application of the Kakutani-Ky Fan Theorem in the theory of ordinary differential equations;Lasota;Bull. Acad. pol. Sci.,1965
5. Principles of Functional Analysis;Schechter,1971