1. W. E. Spicer, in Optical Properties of Solids, F. Abeles (ed.), p. 757, North-Holland Publishing Co., Amsterdam (1972).
2. D. E. Eastman, in Techniques of Metals Research VI, E. Passaglia (ed.), p. 413, Interscience, New York (1972).
3. N. V. Smith, Crit. Rev. Solid State Sci.
2, 45 (1971).
4. D. E. Eastman, in Electron Spectroscopy, Proceedings of an International Conference at Asilomar, D. A. Shirley (ed.), p. 487, North-Holland Publishing Co., Amsterdam (1972).
5. W. E. Spicer, J. Phys. (Paris) Colloq.
34, 19 (1973).