1. J.J. Hopfield, D.G. Thomas, Phys. Rev. 132, 563 (1963)
2. R. Kubo, Dynamical Processes in Solid State Optics (Syokabo, Tokyo, 1967) and further textbooks by this author
3. F. Gervais, B. Piriou, J. Phys. C 7, 2374 (1974); Phys. Rev. B 10, 1642 (1974); ibid. 11, 3944 (1975)
4. H.B. Callen, Thermodynamics and an Introduction to Thermostatistics, 2nd edn. (Wiley, New York, 1985)
5. F. Wooten, Optical Properties of Solids (Academic, New York, 1972)