1. Baak T and Hornyak E J 1961J. Am. Ceram. Soc. 44 541
2. Bamford C R 1961Phys. Chem. Glasses 2 163
3. Bamford C R 1962Phys. Chem. Glasses 3 189
4. Bamford C R 1977 inGlass science and technology (New York: Elsevier)2 p. 35
5. Bates T 1962Modern aspects of vitreous state (ed.) J D Mackenzie (London: Butterworths)2 p. 235