1. Pantano, C. G., Jr., Dove, D. B. and Onoda, G. Y., Jr., (1975), J. Non-Cryst. Solids, 19, 41.
2. Von Hickson, K. (1971), Glastech. Ber., 44, 537.
3. Heuch, L. L. (1975), in Characterization of Materials in Research Ceramics and Polymers, (ed. J. J. Burke and V. Weiss) Syracuse University Press, 211.
4. Mass Spectrum No. 73-185 (1973) Commonwealth Scientific Corporation.
5. Bach, H. and Baucke, F. G. K. (1974), Phys. Chem. Glasses, 15, 123.