1. Bradley, D. C., Prog. Inorg. Chem., 2, 303 (1960).
2. Bradley, D. C., and Kunchur, N. R., J. Chem. Phys., 8, 2258 (1964).
3. Bradley, D. C., and Kunchur, N. R. (unpublished results).
4. Martel, A. E., and Calvin, M., Chemistry of Metal Chelate Compound, 170 (Prentice Hall, Inc., 1952).