1. E. H. PUTLEY,Opt. Laser Technol. 3 (1971) 150.
2. S. T. LIU,Ferroelectrics 10 (1976) 83.
3. L. A. THOMAS, ibid.3 (1971) 231.
4. M. E. LINES and A. M. GLASS, ?Principle and Applications of Ferroelectrics and Related Materials? (Clarendon Press, Oxford, 1977).
5. A. K. BATRA and S. C. MATHUR, in Proceedings of the 1983 IEEE International Symposium on Applications of Ferroelectrics, National Bureau of Standards, Maryland, June 1983.