1. Gurevich, V.L.: Transport in phonon system. Amsterdam: North Holland 1986
2. Claro, F.H., Wannier, C.H.: J. Math. Phys.12, 92 (1971)
3. Petru, Z.K.: Physics of phonons. In: Lecture Notes in Physics. Paszkiewicz, T. (ed.), Vol. 285. Berlin, Heidelberg, New York: Springer 1987
4. Jasiukiewicz, Cz., Paszkiewicz, T.: Z. Phys. B-Condensed Matter77, 209 (1989)
5. Sirotin, Yu.I., Shaskolskaya, M.P.: Principles of crystallophysics. Moscow: Nauka 1979 (in Russian)