1. Quantum Theory of Real Materials (eds. Chelikowsky, J.R., Louie, S.G.) (Kluwer, Dordrecht, 1996)
2. C. Kittel: Introduction to Solid State Physics, 7th edn. (Wiley, New York 1995) p. 37
3. L.M. Falicov: Group Theory and its Physical Applications (Univ. Chicago Press, Chicago 1966)
4. G.F. Koster: Space groups and their representations, in Solid State Physics
5, 173–256 (Academic, New York 1957)
5. G. Lucovsky, A comparison of the long wavelength optical phonons in trigonal Se and Te, Phys. Stat. Sol. (b) 49, 633 (1972)