1. El-Shamy, H.K., El-Aggan, A.M.: J. Amer. Chem. Soc., 75, 1187 (1953)
2. Speranskaya, E.F., Mertsalova, V.E., Kulev, I.I.: Usp. Khim., 35, 2129 (1966)
3. Wünsch, G.: Talanta, 27, 649 (1980)
4. Kiba, N., Takeuchi, T.: Anal. Chim. Acta, 66, 75 (1973)
5. Raĭkhinshtein, Tz., Korobov, N.: J. Gen. Chem. USSR, 2, 661 (1932)