1. A. R. Katritzky and C. W. Rees (Eds.),Comprehensive Heterocyclic Chemistry, Pergamon Press, Oxford, 1984. Vol. 1, p. 144.
2. M. Mohan, M. P. Gupta, L. Chandra and N. K. Jha,Inorg. Chim. Acta. 151, 61 (1988).
3. C. R. Gray,Arch. Int. Pharmacodyn. Ther.,165, 328 (1967).
4. F. D. Popp,J. Heterocyclic Chem.,21, 617 (1984).
5. K. Burger,Coordination, Chemistry Experimental Methods, 1st. Edit. Butterworths, London, 1973, p. 294.