1. Merzbacher, E., Lewis, H.W.: In: Handbuch der Physik (ed. by S. Fl�gge), Vol. 34, p. 166, Berlin-G�ttingen-Heidelberg: Springer 1958
2. Garcia, J.D., Fortner, R.J., Kavanagh, T.M.: Rev. Mod. Phys.45, 111 (1973)
3. See e.g. Hansteen, J.M.: In: Adv. in Atomic and Molecular Physics (ed. by D.R. Bates and B. Bederson), Vol. 11, p. 299, New York: Academic Press 1975
4. See e.g. Richard, P.: In: Atomic Inner-Shell Processes (ed. by B. Crasemann), p. 73, New York: Academic Press 1975
5. Basbas, G., Brandt, W., Laubert, R.: Phys. Rev. A7, 983 (1973)