1. H. Pollak, Phys. Stat. Sol. 2 (1962) 270.
2. W.M. Visscher, Phys. Rev. 134(1964)A965.
3. D. Horváth, D.L. Nagy and K. Vladár, Hyp. Int. 30 (1986) 297.
4. H.H. Wickman and G.K. Wertheim, in:Chemical Applications of Mössbauer Spectroscopy, eds. V.I. Goldanskii and R.H. Herber (Academic Press, New York, 1968) p. 548.
5. J.P. Adloff and J.M. Friedt, in:Mössbauer Spectroscopy and its Applications (IAEA, Vienna, 1972) p. 301.