1. Schwartz, K., and Folz, C. M., J. Am. chem. Soc.79 (1957) 3292.
2. Rotruck, J. T., Pope, A. L., Ganther, H. E., Swanson, A. B., Hafeman, D. G., and Hoekstra, W. G., Science179 (1972) 288.
3. Frost, D. V., CRC Crit. Rev. Toxic.1 (1972) 467.
4. Diplock, A. T., CRC Crit. Rev. Toxic.4 (1976) 271.
5. Rosenfeld, I. and Beath, O. A., Selenium, Geobotany, Biochemistry, Toxicity, and Nutrition. Academic Press, New York 1964.