1. V. I. Arnol'd, Dynamical Systems. I. Ordinary Differential Equations and Smooth Dynamical Systems, Encyclopaedia of Math. Sci., Vol. 1, D. V. Anosov and V. I. Arnol'd (Eds.), Springer-Verlag, Berlin (1988) x+233 pp.
2. M. Artin, “On the solutions of analytic equations,” Invent. Math., 5 (1968), 277–291.
3. Princeton Mathematical Series;M. S. Baouendi,1999
4. M. S. Baouendi, H. Jacobowitz, and F. Treves, “On the analyticity of CR mappings,” Ann. of Math., 122, No. 2 (1985), 365–400.
5. Progress in Mathematics;A. Bellaïche,1996