Euler-Lagrange inclusions and existence of minimizers for a class of non-coercive variational problems. Crasta, Graziano, Malusa, Annalisa (2000) Journal of Convex Analysis
Extremal solutions to a class of multivalued integral equations in Banach space. Aizicovici, Sergiu, Papageorgiou, Nikolaos S. (1992) Journal of Applied Mathematics and Stochastic Analysis