1. P. L. Baynton, H. Rawson, and J. E. Stanworth, Proc. Fourth Internat. Glass Congr. (Paris) 1956 (Imprimerie Chaix Paris 1957); Ceram. Abstr. July (1959) p. 197e.
2. J. Rao, Phys. Chem. Glasses 4 (1963) 22; J. Amer. Ceram. Soc. 47 (1964) 455.
3. W. B. White, J. Amer. Ceram. Soc. 48 (1965) 108.
4. H. Rawson, ?Inorganic Glass Forming Systems? (Academic Press, London, 1967).
5. N. Norman, Acta Cryst. 10 (1957) 370.