1. G. Ooms and R.A. van Santen, Recueil des Travaux Chimiques des Pays Bas 106 (1987) 69?71.
2. C.R.A. Catlow and W.C. Mackrodt, eds.,Computer Simulation of Solids, Lecture notes in Physics no. 166 (Springer-Verlag, Berlin, 1982).
3. R.A. Jackson and C.R.A. Catlow, appearing in: Molecular Simulations.
4. G.V. Gibbs, E.P. Meagher, M.D. Newton and D.K. Swanson, in:Structure and Bonding in Crystals, Vol. I, eds. Keeffe and Alexandra Navrotsky (Academic Press, New York, 1981).
5. M. O'Keeffe, B. Domenges and G.V. Gibbs, J. Phys. Chem. 89 (1985) 2304?2309.