1. H. E. Helms, R. A. Johnson and L. E. Groseclose, in Proceedings of the Twenty-Third Automotive Technology Development Contractors' Coordination Meeting, P-165 (Society of Automotive Engineers, Warrendale, Pennsylvania, 1986) p. 137.
2. D. Carruthers and L. Lindberg, in Proceedings of the Third International Symposium on Ceramic Materials and Components for Engines, edited by V. J. Tennery (American Ceramic Society, Westerville, Ohio, 1989) p. 1258.
3. R. Kossowsky, D. G. Miller and E. S. Diaz, J. Mater. Sci.
10 (1975) 983.
4. G. D. Quinn, ibid.
25 (1990) 4361.
5. Idem, ibid.
25 (1990) 4377.