1. H. Wada andM. J. Wang, in ?Proceedings of the International Conference on Whisker- and Fiber-Toughened Ceramics,? edited by R. A. Bradley, D. E. Clark, D. C. Larsen and J. O. Stiegler (ASM International, 1988) p. 63.
2. H. Wada, in ?Proceedings of the International Symposium on Advances in Processing and Application of Ceramic and Metal Matrix Composites,? edited by H. Mostaghaci, (Pergamon Press, 1989) p. 3.
3. M. J. Wang andH. Wada, in ?Preparation and Properties of Silicon Nitride Based Materials?, edited by D. A. Bonnell and T. Y. Tien (Trans Tech, 1989) p. 267.
4. Idem, J. Mater. Sci.25 (1990) 1690.
5. H. Wada andL. Wang,ibid. 27 (1992) 1528.