1. P. Boolchand and D. McDaniel, in:Studies of High T c Superconductors, ed. A.V. Narliker, Vol. 4 (Nova Science Publishers, Inc., 1990) Ch. 3, and references therein.
2. C. Saragovi-Badler, F. Labenski de Kanter, M.T. Causa, S.M. Dutrus, C. Fainstein, L.B. Steren, M. Tovar and R. Zysler, Solid State Comm. 66 (1988) 381.
3. C. Saragovi, F. Labenski, C. Fainstein and N. Veglio,Proc. Latin American Conf. on the Applications of the Mössbauer Effect, 346, Rio de Janeiro 1988, eds. E. Baggio-Saitovich, E. Galvão da Silva and H.R. Rechenberg ((World Scientific, Singapore).
4. I. Tittonen, J. Hietaniemi, J. Huttunen, T. Karlemo, M. Karppinen, T. Katila, J. Lindén, L. Niinistö and K. Ullakko,Int. Conf. on the Applications of the Mössbauer Effect, Budapest, 1989 Hyp. Int. 55 (1990) 1405.
5. D. Barb, presented at the International Conference on the Applications of the Mössbauer Effect, Budapest, 1989.