1. A Ali, A K Nain, D Chand and B Lal Indian J. Chem. 44A 511 (2005)
2. V Seetharaman, S Kalyansundaram and A Gopalan Indian J. Pure Appl. Phys. 42 735 (2004)
3. S Acharya, S K Das and B B Swain Acoust. Lett. 21 52 (1997)
4. V Kannappan and Jaya R Santhi Indian J. Pure Appl. Phys. 43 167 (2005)
5. P K Mishra, A Dash, B Behera, B B Swain and V Chakravorthy Acoust. Lett. 19 99 (1995)