1. Casassas, E., Esteban, M., and Alier, S., Collect. Czech. Chem. Commun., 1989, vol. 64, no.5, p. 1219.
2. Latimer, G., Talanta, 1968, vol. 15, no.1, p. 1.
3. Toropova, V.F., Budnikov, G.K., and Maistrenko, V.N., Zh. Obshch. Khim., 1974, vol. 44, no.2, p. 364.
4. Farias, P.A.M. and Ohara, A.K., Anal. Chem., 1992, vol. 342, p. 87.
5. Dorofeeva, V.F., Rogatinskaya, S.L., and Kreshkov, A.P., Zh. Anal. Khim., 1979, vol. 34, no.5, p. 913.