1. G.N. Rao, Hyp. Int. 7 (1979) 141.
2. B. Singh, V.R.K. Murty and H.S. Hans, Proc. Int. Conf. on hyperfine interactions, Uppsala, 1974, ed. E. Karlsson and R. Wäppling, p.174.
3. P.N. Tandon and H.G. Devare, Hyp. Int. 2 (1976) 196.
4. P. Raghavan, R.S. Raghavan and M. Senba, Abstracts Int. Conf. on hyperfine interactions, Berlin, 1980, ed. G. Kaindl and H. Haas, C49-I.
5. A.K. Dhar, B. Singh, V. Singh and H.S. Hans, J. Phys. Soc. Japan 32 (1972) 1531.