1. Anon 1950The wealth of India, Raw materials (New Delhi: CSIR) Vol. 2
2. Arrigo G D and Sette D 1968J. Chem. Phys. 48 691
3. Bhattacharya A C and Deo B B 1981Indian J. Pure Appl. Phys. 19 1172
4. Bhattacharya A C 1980Int. Conf. and Exhibition on Ultrasonics, New Delhi, Conf. Papers, p. 284
5. Bhattacharya A C 1981J. Pure Appl. Ultra. 3 7