1. K. Danzer, H. Ehrhardt, M. Geissler, G. Ehrlich, F. Gadow,Anal. Chim. Acta 1979,105, 1.
2. G. Ehrlich, H. Mai,Proceedings of the 3rd Conference Festk�rperanalytik, Karl-Marx-Stadt, 1981, Vol. 1, Technical University, Karl-Marx-Stadt, 1982, p. 97.
3. A. D. Wilson,Analyst 1964,89, 18.
4. P. Boha?ek,Coll. Czechoslov, Chem. Commun. 1977,4, 2983 and 3003.
5. J. Inczedy,Talanta 1982,29, 643.