G. Iooss and M. Adelmeyer, Topics in bifurcation theory and applications. Advanced Series in Non Linear Dynamics 3, World Scientific, 1992.

G. Iooss and E. Lombardi, Polynomial Normal Forms with Exponentially Small Remainder for Analytic Vector Fields. Prépublication de l'Institut Fourier n o, p.631, 2004.
URL : https://hal.archives-ouvertes.fr/hal-00013597

E. Lombardi, Oscillatory integrals and phenomena beyond all algebraic orders. With applications to homoclinic orbits in reversible systems, Lecture Notes in Mathematics, vol.1741, 2000.
DOI : 10.1007/bfb0104102