1. C.E. Brion, S. Daviel, R. Sodhi and A.P. Hitchcock, in “X ray and Atomic Inner-Shell Physics 1982”, B. Crasemann, ed., AIP Conference Proceedings No. 94, p. 429
2. S.E. Schnatterly, Solid State Physics, Vol. 34, Academic Press (1979), p. 275
3. J.A.D. Matthew and S.M. Girvin, Phys. Rev. B 24: 2249 (1981)
4. R.J. Celotta and R.H. Huebner, in “Electron Spectroscopy: Theory, Techniques and Applications” Vol. 3, C.R. Brundle and A.D. Baker, eds., Academic Press (1979), p. 41
5. R.A. Bonham, ibid. p. 127