1. J. A. Mangels andW. Trela, in ?Advances in Ceramics?, Vol. 9 edited by J. A. Mangels (American Ceramic Society, New York, 1984) p. 220.
2. P. A. Willermet, R. A. Pett andT. J. Whalen,Bull. Amer. Ceram. Soc. 57 (1978) 744.
3. R. S. Storm, R. W. Ohnsorg andF. J. Frechette,J. Power Eng. 104 (1982) 601.
4. I. Peltsman andM. Peltsman,Interceram. 4 (1984) 56.
5. J. A. Mangels, US Patent 3 926 656, 16 December (1975).