1. L. J. BOGERT, G. M. BRIGGS, D. H. CALLOWAY, Nutrition and Physical Fitness, W. B. Saunders Company, Philadelphia, PA, 1973.
2. E. J. UNDERWOOD, Trace Elements in Human and Animal Nutrition, Academic Press, New York, N. Y., 1971.
3. C. BERGERIOUX, L. ZIKOVSKY, J. Radioanal. Chem., 47 (1978) 173.
4. P. ILA, P. JAGAM, EUROANALYSIS III, Dublin, 1978, p. 347.
5. L. S. CHUANG, D. A. MILLER, W. P. LAY, W. Y. CHIU, Proc. Intern. Conf. in Modern Trends in Activation Analysis, Munich, 1976, p. 938.