1. F. A. Kroger, The Chemistry of Imperfect Crystals (North-Holland, Amsterdam, 1974) vol 2, p9.
2. T.Y. Tan and U. Gösele, Appl. Phys. Lett., 52, 1240 (1988).
3. R.F. Brebrick, J. Phys. Chem. Solids, 40, 177 (1979).
4. G. Brouwer, Philips Res. Rept., 9, 366 (1954).
5. P.G. Shewmon, Diffusion in Solids (McGraw-Hill, New York, 1963).