1. V. A. Agladze and Yu. P. Ponomarev, ?The group-theoretic approach to the analysis of controllable dynamical systems,? Kibernetika, (Kiev), No. 25, 8?11 (1984)
2. A. A. Agrachev, ?A necessary condition for second-order optimality in the general nonlinear case,? Mat. Sb.,102, No. 4, 551?568 (1977).
3. A. A. Agrachev, ?Necessary and sufficient extremal conditions for smooth controllable systems,? ICM Warsaw, Short Communications XII, Section 14: Control theory and optimization, p. 29 (1982).
4. A. A. Agrachev and S. A. Vakhrameev, ?Chronological series and the Cauchy-Kovalevskaya theorem,? in: Problems of geometry. Vol. 12, Itogi nauki i tekhn. All-Union Institute for Scientific and Technical Information (VINITI), Akad. Nauk SSSR, Moscow, 165?189 (1981).
5. A. A. Agrachev and S. A. Vakhrameev, ?Nonlinear control systems of constant rank and bang-bang conditions for extremal controls,? Dokl. Akad. Nauk SSSR,279, No. 2, 265?269 (1984).