1. Alber, Ya.I.: Metric and generalized projection operators in Banach spaces: properties and applications. In: Kartsatos, A.G.(eds) Theory and Applications of Nonlinear Operators of Accretive and Monotone Type, pp. 15–50. Marcel Dekker, New York (1996)
2. Alber, Ya.I., Ryazantseva, I.P.: Nonlinear Ill-posed Problems of Monotone Type. Springer, Dordrecht (2006)
3. Asplund, E.: Averaged norms. Israel J. Math. 5, 227–233 (1967)
4. Aubin, J.-P.: Optima and Equilibria. Springer, Berlin Heidelberg New York (1993)
5. Browder, F.E.: Nonlinear elliptic boundary problems. Bull. Am. Math. Soc. 69, 299–301 (1963)