1. Y. Ozaki: Ceramics, 16, 7, p. 570 (1981) (in Japanese)
2. Y. Ozaki: Ceramics, 16, 8, p. 675 (1981) (in Japanese)
3. Y. Ozaki: New Ceramic Powder Handbook, p. 79, Science Forum (1983) (in Japanese)
4. Y. Ozaki: Kagaku Kougaku, 46, 10, p. 13 (1982) (in Japanese)
5. P.K. Gallagher, J. Thomson, Jr.: J. Am. Ceram. Soc., 48, 12, p. 644 (1965)