1. Jona F.,Shirane G., Ferroelectric crystals, Pergamon Press, 1962.
2. Burfoot J. C., Ferroelectrics, D. Van Nostrand Comp. LTD., London 1967.
3. Zeludev I. S., Fizika kristalličeskich dielektrikov (in Russian), Nauka, Moscow 1968.
4. Ivanchik I. I., Fiz. tverd. tela3 (1961), 3731.
5. Holodenko L. P., Fiz. tverd. tela5 (1963), 897.