1. P. W. Mcmillian, in “Glass-ceramics” (Academic Press, London, 1979) p. 1.
2. J. A. Topping, P. Fuchs and M. K. Murthy, J. Amer. Ceram. Soc.
57 (1974) 205.
3. K. Yoji and T. Shoji, ibid.
57 (1971) 131.
4. M. R. Simon, Amer. Ceram. BulL.
68 (1989) 1956.
5. H. S. Joseph and J. S. Catherine, ibid.
68 (1989) 1949.