1. K. C. Kalra, V. K. Sharma, and A. Katoch, Indian J. Chem. 35A, 390 (1996).
2. P. P. Singh, P. K. Sharma, and S. Maken, Indian J. Chem. 31A, 619 (1992).
3. V. K. Sharma and Romi, Can. J. Chem. 79, 1910 (2001).
4. V. K. Sharma and Romi, Indian J. Chem. 41A,1167 (2002).
5. V. K. Sharma and S. Kumar, Thermochim. Acta 413, 255 (2004).