1. R. Gopal and S. Agarwal,J. Chem. Thermodyn. 8, 4750 (1975).
2. R. Gopal and S. Agarwal,J. Chem. Thermodyn., in press.
3. L. Simeral and R. L. Amey,J. Phys. Chem. 74, 1443 (1970).
4. J. N. Butler,J. Anal. Chem. 39, 1799 (1967).
5. I. A. Vogel,Practical Organic Chemistry (Longmans Group Ltd., London, 1971). pp. 170?176.