1. C. Kittel,Introduction to Solid State Physics (J. Wiley, New York, 1953).
2. P. G. Klemens, inHandb. d. Phys. Vol. 14 (Springer, Berlin, 1956), p. 198.
3. G. L. Eesley,Phys. Rev. B33:2144 (1986).
4. P. G. Klemens, inThermal Conductivity, R. P. Tye, ed. (Academic Press, London, 1969), Vol. 1, p. 1.
5. J. S. Dugdale,Science 134:77 (1961).