1. Akiama, Y., (1987): J. Electronic Eng., 24, 76.
2. Albsmeier, H., (1971): Frequenz, 25, 74.
3. Arlt, G., (1982): Ferroelectrics 40, 149.
4. Austan, D.H. and A.M. Glass, (1972): Appl. Phys. Lett., 20, 398.
5. Bast, U., D. Cramer, and A. Wolff, 1990: Proc. 7th. CIMTEC-World Ceramics Congress, Montecatini Terme, Italy, pp. 2005–2015.