1. Directionally Lipschitzian mappings on Baire spaces;Borwein;Canad. J. Math.,1984
2. Optimization and Nonsmooth Analysis;Clarke,1983
3. Generalized gradients and applications;Clarke;Trans. Amer. Math. Soc.,1975
4. Generalized gradients of Lipschitz functionals;Clarke;Adv. in Math.,1981
5. Convergence problems for functionals and operators;De Giorgi,1979