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2. P.-G. de Gennes, The Physics of Liquid Crystals (Claredon Press, Oxford, 1974; Mir, Moscow, 1977).
3. Physical Properties of Liquid Crystals, Ed. by D. Demus et al. (Wiley-VCH, Weinheim, 1999), p. 447.
4. A. P. Kapustin and O. A. Kapustina, Acoustics of Liquid Crystals (Nauka, Moscow, 1986) [in Russian].
5. O. A. Kapustina, Kristallografiya 54(2), 345 (2009) [Crystallogr. Rep. (Engl. Transl.) 54 (2), 320 (2009)].