1. R. Vračar et al., Theory of Metallurgical Process-Handbook, University of Belgrade (1986) (in Serbian).
2. T. Rosenqvist, Principles of Extractive Metallurgy, McGraw-Hill, London (1983).
3. Kirk-Othmer, Encyclopedia of Chemical Technology, Wiley, New York, 12, 1967, pp. 887–905.
4. Ullmann's Encyclopedia of Industrial Chemistry, VCH Verlagsgesellschaft, Weinheim, A16, 1990, pp. 77–121.
5. McGraw-Hill Encyclopedia of Science and Technology, McGraw-Hill Book, London, 8, 1971, pp. 98–101.