1. Arutyunov, A.V., Aseev, S.M., and Blagodatskikh, V.I., First-order necessary
conditions in the problem of optimal control of a differential inclusion with phase constraints,
Russ. Acad. Sci. Sb. Math., 1994, vol. 79, no. 1,
pp. 117–139.
2. Mordukhovich, B.S., Variational Analysis and
Generalized Differentiation II. Application, Berlin:
Springer, 2006.
3. Davydov, A.A., Normal form of a differential equation, not solvable for the
derivative, in a neighborhood of a singular point, Func. Anal. Its
Appl., 1985, vol. 19, pp. 81–89.
4. Davydov, A., Ishikawa, G., Izumiya, S., and Sun, W.-Z., Generic singularities
of implicit systems of first order differential equations on the plane, Jpn. J. Math., 2008, vol. 3, no. 1, pp. 93–120.
5. Remizov, A.O., Implicit differential equations and vector fields with
non-isolated singular points, Sb. Math., 2002, vol. 193,
no. 11, pp. 1671–1690.