1. A. H. Wilson,Theory of Metals (Cambridge University Press, London, 1953), 2nd edn., pp. 50–51.
2. R. Becker,Theorie der ElektrizitÄt (Teubner, Berlin, 1933), Vol. 2, Sec. 56; see also, Ref. 3, p. 194.
3. N. W. Ashcroft and N. D. Mermin,Solid State Physics (Saunders, Philadelphia, 1976), pp. 213–235.
4. G. H. Wannier,Elements of Solid State Theory (Cambridge University Press, London, 1960), pp. 190–194.
5. W. A. Harrison,Solid State Theory (Dover, New York, 1979), pp. 64–71.