1. Hendry, A. and Jack, K. H. In Special Ceramics, Vol. 6, Popper, P. (Ed.), British Ceramic Research Association, Stoke-on-Trent, p. 199, 1975.
2. Komeya, K. and Inoue, H. Journal of Materials Science, 10 (1975) 1243.
3. Ish-shalom, M. Journal of Materials Science Letters, 1 (1982) 4.
4. Lee, J. G. and Cutler, I. B. American Ceramic Society Bulletin, 58 (1979) 9.
5. Gavrish, A. M., Boyarina, I. L., Degtyareva, E. V., Puchkov, A. B., Zkukova, Z. D., Gul’ko, N. V. and Tarasova, L. A. Inorganic Materials, 18 (1982) 46.