1. P D Sahare, S V Moharil and B D Bhasin,J. Phys.: Appl. Phys. D22, 971 (1989)
2. M Ohta, M Sakaguchi and M Sato,Denki Kagaku 60, 881 (1993)
3. T K Seshagiri, A G I Dalvi and M D Sastry,J. Phys. C21, 5891 (1988)
4. M D Sastry and A G I Dalvi, inHandbook on Physics and Chemistry of the actinides edited by A J Freeman and C Keller (Elsevier Science Publishers, Amsterdam, 1991) ch. 8, p. 411
5. T K Seshagiri, V Natarajan and M D Sastry,Pramana — J. Phys. 44, 211 (1995)