1. Greenwood, N. N. and Earnshaw, A. 1984.The Chemistry of the Elements, 3759883Oxford: Pergamon Press.
2. Sindeeva, N. D. 1964.Mineralogy and Types of Deposits of Selenium and Tellurium, 19186New York: Interscience Publ.
3. Jennings, P. H. and Yannopoulos, J. C. 31