1. Gradients généralisés de Clarke;Aubin;Ann. Sci. Math. Québec,1978
2. N. Bourbaki, “Variétés différentielles et analytiques,” Hermann, Paris.
3. Necessary Conditions for Nonsmooth Problems in Optimal Control and the Calculus of Variations;Clarke,1973
4. Generalized gradients and applications;Clarke;Trans. Amer. Math. Soc.,1975
5. A new approach to Lagrange multipliers;Clarke;Math. Oper. Res.,1976