1. Springer Ser. Solid-State Sci., Vol.40;K Seeger,1991
2. R. Dingle: Proc. 13th Int’l Conf. on Physics of Semiconductors ed. by F.G. Fumi (North-Holland, Amsterdam 1976)
3. A. Yariv: Quantum Electronics, 3rd edn. (Wiley York, New York 1988) pp. 267–268
4. A. Yariv: Quantum Electronics, 3rd edn. (Wiley York, New York 1988) p. 270
5. A. Yariv: Quantum Electronics, 3rd edn. (Wiley York, New York 1988) p. 272