1. C. Kittel Introduction to Solid State Physics (Wiley, New York 1966 )
2. W.E. Spicer In [Ref.1.101, p.139]
3. M. Cardona, L. Ley (eds.): Photoemission in Solids I,,II, Topics Appl. Phys., Vols.26, 27 (Springer, Berlin, Heidelberg 1978/79)
4. S. Hfner. Introduction to Photoemission Spectroscopy, Springer Ser. Solid-State Sci., Vol.82 (Springer, Berlin, Heidelberg 1989) in print
5. K. Siegbahn, C. Nordling, A. Fahlman, R. Nordberg, K. Hamrin, J. Hedman, G. Johansson, T. Bergmark, S.-E. Karlsson, I. Lindgren, B. Lindberg: ESCA (Atomic, Molecular and Solid State Structure Studied by Means of Electron Spectroscopy) (North-Holland, Amsterdam 1967 )