1. R. de Laer Kronig, W.J. Penney: Proc. Roy. Soc. London A130, 499 (1930)
2. A. Nussbaum: Semiconductor Device Physics (Prentice-Hall, Englewood Cliffs, N.J. 1962) Sects. 1.9 and 1.13
3. R.A. Smith: Wave Mechanics of Crystalline Solids, 2nd edn. (Chapman and Hall, London 1969) Sect. 6.2
4. J.P. McKelvey: Solid-State and Semiconductor Physics (Harper and Row, New York 1966) Sect. 8.6
5. E.O. Kane: J. Phys. Chem. Solids 1, 249 (1957)