1. Keller, A. (1957) Phil. Mag.
2, 1171.
2. Organ, S.J. and Keller, A. (1985) J. Mater. Sci. 20, 1571.
3. Organ, S.J. and Keller, A. (1985) J. Mater. Sci.
20, 1602.
4. Hoffman, J.D., Davis, G.T. and Lauritzen, J.I. (1976) in Treatise on Solid State Chemistry, vol. 3, (ed. N.B. Hannay) Plenum Press, New York.
5. Sadler, D.M. (1983) Polymer
24, 1401.