1. Zarzycki, J. (1991) Glasses and the vitreous state, Cambridge university Press, Cambridge.
2. Zarzycki, J, Prassas, M., and Phalippou J. (1982) J. Mater. Sci. 17, 3371.
3. Mackenzie, J. (1960) (1962) (1964) Modern aspects of the vitreous state, I,II,III, Butterworth, London.
4. Sun, K. (1947) J. Am.Cer.Soc. 30, 277.
5. Sen, S. (2000) Atomic environment of high-field strength Nd and Al cations as dopants and major components in silicate glasses: a Nd LIII-edge and Al K-edge X-ray absorption spectroscopic study, J. Non. Cryst. Solids 261, 226–236.