ON THE CONTROLLABILITY OF TRAJECTORIES IN OPTIMAL CONTROL PROBLEMS WITH PHASE CONSTRAINTS Article Arutyunov A.V., Chernikova N.Yu., Sklyar Grigory M. Geometric control theory (Russian) (Moscow, 1998). Vseross. Inst. Nauchn. i Tekhn. Inform. (VINITI), Moscow. 1999. P. 49-56
PARTIAL DIFFERENTIAL AND INTEGRAL EQUATIONS (NEWARK, DE, 1997) Conference proceedings Kluwer Acad. Publ., Dordrecht.