1. L. D. Landau and E. M. Lifshitz, Statistical Physics, 3rd edition, Oxford, Pergamon, 1981.
2. J. C. Toledano and P. Toledano, The Landau Theory of Phase Transitions, World Scientific, Singapore, 1987.
3. A. P. Levaniuk and A. S. Sigov, Defects and Structural Phase Transitions, Gordon and Breach, New York, 1988.
4. J. Birman, Phys. Rev. Lett. 17, 1216 (1966).
5. G. A. Korn, Mathematical Handbook for Scientists and Engineers, 2nd ed., 1968.