1. Allis, W. P., 1956, in “Handbuch der Physik,” Flügge, S. ( Ed. ), Springer, Berlin.
2. Bayle, P., J. Vacquie, and M. Bayle, 1986, Phys. Rev. A 34, 360.
3. Boeuf, J. P., and E. Marode, 1982, J. Phys. D 15, 2069.
4. Boeuf, J. P., and P. Ségur, 1987, in “Interactions Plasmas Froids Materiax,” C. Lejeune, (Ed.), Les Editions de Physique, Les Ulis, France.
5. Braglia, G. L., L. Romano, and M. Dilligenti, 1982, Lett. Nuovo Cim. 35, 193.