1. L. Ambrosio, O. Ascenti, and G. BUTAZZO, Lipschitz regularity for minimizers of integral functionals with highly discontinuous integrands, J. Math. An. Appl., 142, 1989, pp. 301–316.
2. A. V. Arutyunov and S. M. Aseev, Investigation of the degeneracy phenomenon of the maximum principle for optimal control problems with state constraints, SIAM J. Control Optim., 35, 1977, pp. 930–952.
3. A. V. Arutyunov, S. M. Aseev, and V. I. Blagodatskikh, First order necessary conditions in the problem of optimal control of a differential inclusion with phase constraints, Russian Acad. Sci. Sb. Math., 79, 1994, pp. 117–139.
4. S.M. Aseev, Method of smooth approximations in the theory of necessary conditions for differential inclusions, preprint.
5. H. Attouch, Variational Convergence for Functions and Operators, Applicable Mathematics Series, Pitman, London, 1984.