1. A. L. MOXPON, Science, 88 (1938) 81.
2. G. YANG, J. CHEN, Z. WEN, K. GE, L. ZHU, X. C. CHEN X. S. CHEN, Adv. Nutr. Res., 6 (1984) 203.
3. Y. SHU-YU, C. Ya-JUN, G. XIN-LAN, H. CHONG, L. WEN-GUANG, G. HUI-MIN, X. JINRONG, Biological Trace Element Research, Humana Press, 1985.
4. M. F. ROBINSON, Clinical, Biochemical and Nutritional Aspects of Trace Elements, Alan R. Liss, New York, 1982.
5. G. V. IYENGAR, W. E. KOLLMER, H. J. M. BOWEN, The Elemental Composition of Human Tissues and Body Fluids, Verlag Chemie, Weinheim, 1978.