1. Blake, C. A., Baes, C. F., Brown, K. B., Coleman, C. F., White, I. C.: Proc. Second Intern. Conf. Peaceful Uses of Atomic Energy, Geneva 28, 289 (1958)
2. Coates, R. L., Jones, M. M.: J. Inorg. Nucl. Chem. 37, 443 (1975)
3. Föhring, R., Specker, H.: Fresenius Z. Anal. Chem. 264, 378 (1973); 273, 429 (1975)
4. Gauss, W., Moser, P., Schwarzenbach, G.: Helv. Chim. Acta XXXV, Fasc. VII (1952)
5. Irving, H., Al-Niaimi, N. S.: D. Phil. Thesis, Oxford 1964