1. E. Spenke: Electronic Semiconductors (Mc Graw-Hill, New York 1965) Chap. 8
2. E. Schrödinger: Statistical Thermodynamics (Cambridge Univ. Press, Cambridge 1948)
3. J.S. Blakemore: Semiconductor Statistics (Pergamon, Oxford 1962) Appendix B J. McDougall, E.C. Stoner: Philos. Trans. A 237, 67 (1938)
4. P. Rhodes: Proc. Roy. Soc. London A 204, 396 (1950)
5. H.J. Goldsmid: Problems in Solid State Physics (Academic, New York 1969) p.354