1. Hartmann, H., Mach, R. and Selle, B. (1982) Curr. Top. Mater. Sci, 9, 1.
2. Bhargava, R. (1982) J. Cryst. Growth, 59, 15.
3. Bhargava, R. (1988) J. Cryst. Growth, 86, 873.
4. Dean, P.J. (1979) In Defects and Radiation Effects in Semiconductors, Inst. Phys. Conf. Ser., 46, 100.
5. Marfaing, Y. (1981) Prog. Cryst. Growth Charact., 4, 317.