1. H. Stapelfeldt, D. G. Papaioannou, L. D. Noordam, and T. E. Gallaher, Phys. Rev. Lett. 67, 3223 (1991).
2. Atoms, Ions and Molecules in a Strong Laser Field, Ed. by N. B. Delone, J. H. Eberly, M. V. Fedorov, and G. Mainfray, Laser Phys. 3, 219 (1993).
3. N. B. Delone and V. P. Kraĭnov, Usp. Fiz. Nauk 165, 1295 (1995).
4. I. M. Beterov, I. I. Ryabtsev, E. V. Pestryakov, et al., Opt. Spektrosk. 81, 383 (1996) [Opt. Spectrosc. 81, 346 (1996)].
5. A. V. Smith, J. E. M. Goldsmith, D. E. Nitz, and S. J. Smith, Phys. Rev. A 22, 577 (1980).