1. A. Ya. Kruger, Generalized Differentials of Nonsmooth Functions [in Russian], Minsk (1981);
2. Manuscript Deposited in the All-Union Institute of Scientific and Technical Information at No. 1332-81.
3. B. Sh. Mordukhovich, ?The maximum principle in a problem of time optimal response with nonsmooth constraints,? Prikl. Mat. Mekh.,40, No. 6, 1014?1023 (1976).
4. A. Ya. Kruger, Subdifferentials of Nonconvex Functions and Generalized Directional Derivatives [in Russian], Minsk (1977);
5. Manuscript Deposited in the All-Union Institute of Scientific and Technical Information at No. 2661-77.