1. K. Tanabe, in ?Solid Acids and Bases, Their Catalytic Applications? (Academic, New York, 1970).
2. K. Tanabe, T. Sumiyoshi, K. Shibata, T. Kiyoura andJ. Kitagawa,Bull. Chem. Soc. Jpn 47 (1974) 1064.
3. K. Araka andK. Tanabe,ibid. 53 (1980) 299.
4. R. C. Buchanan, ?Ceramic Materials for Electronics? (Dekker, New York, 1986) p. 154.
5. B. Jaffe, W. R. Cook andH. Joffe, ?Piezoelectric Ceramics? (Academic, London, 1971) p. 237.