1. H. de Waard, S. Bukshpan and G.J. Kemerink, Hyperfine Interactions 5 (1977) 45.
2. S.M. Hu, in: Atomic Diffusion in Semiconductors, ed. D. Shaw (Plenum Press, London, 1973) p. 261.
3. J.F. Vetelino and S.S. Mitra, Phys. Rev. 178 (1969) 1439.
4. E. Antoncik, to be published in Hyperfine Interactions.
5. H. de Waard, in: M�ssbauer Effect Data Index, eds. J.G. Stevens and V.E. Stevens) (Adam Hilger, London, 1974) p. 447.