1. É. E. Anders, B. Ya. Sukharevskiĭ, and L. S. Shestachenko, Fiz. Nizk. Temp. (Kiev) 5(7), 783 (1979).
2. G. L. Belen’kiĭ, R. A. Suleĭmanov, N. A. Abdullaev, and V. Ya. Shteĭnshraĭber, Fiz. Tverd. Tela (Leningrad) 26(12), 3560 (1984) [Sov. Phys. Solid State 26 (12), 2142 (1984)].
3. N. A. Abdullaev, R. A. Suleĭmanov, M. A. Aldzhanov, and L. N. Alieva, Fiz. Tverd. Tela (St. Petersburg) 44(10), 1775 (2002) [Phys. Solid State 44 (10), 1859 (2002)].
4. M. Born and Huang Kun, Dynamical Theory of Crystal Lattices (Clarendon, Oxford, 1954; Inostrannaya Literatura, Moscow, 1958).
5. L. D. Landau and E. M. Lifshitz, Course of Theoretical Physics, Vol. 7: Theory of Elasticity (Pergamon, New York, 1986; Nauka, Moscow, 1987).