1. J.P. Aubin and H. Frankowska,Set-valued analysis.Birkhaüser, Boston (1990).
2. M.S. Bazaraa and C.M. Shetty,Foundations of optimization.Springer-Verlag, Berlin (1976).
3. M.S. Bazaraa and C.M. Shetty,Nonlinear programming.John Wiley & Sons, New York (1979).
4. V.F. Demyanov and A.M. Rubinov,Constructive nonsmooth analysis.Verlag Peter Lang, Frankfurt am Main (1995).