1. V. A. Komarov, Zh. Anal. Khim.31, 366 (1976).
2. P. C. Uden and D. E. Henderson, Analyst102, 889 (1977).
3. D. N. Sokolov, Usp. Khim.46, 740 (1977).
4. J. Maslowska and S. Starzyński, Wiad. Chem.36, 669 (1982).
5. V. P. Mikhaylenko, I. P. Sereda, and A. N. Korol, Zh. Anal. Khim.34, 2260 (1979).