T. Donohue and J. L. Rullier, Electron trajectories in a helical free-electron laser with an axial guide field, Physical Review E, vol.49, issue.1, p.766, 1994.
DOI : 10.1103/PhysRevE.49.766

URL : https://hal.archives-ouvertes.fr/in2p3-00102639

P. Freund, T. M. Antonsen, and J. , Principles of Free-electron Lasers
DOI : 10.1007/978-94-011-2316-7