1. V. G. Vaks, Introduction to Microscopic Theory of Ferroelectrics (Nauka, Moscow, 1973) [in Russian].
2. R. Blinc and B. Zeks, Soft Modes in Ferroelectrics and Antiferroelectrics (North-Holland, Amsterdam, 1974; Mir, Moscow, 1975).
3. M. Lines and A. Glass, Principles and Applications of Ferroelectrics and Related Materials (Oxford Univ., Oxford, 1977).
4. B. A. Strukov, and A. P. Levanyuk, Basic Physics of Ferroelectricity in Crystals (Nauka, Moscow, 1995) [in Russian].
5. R. Blinc and S. Svetina, Phys. Rev. 147, 430 (1966).