1. P. G. Jeffery , Methods of Rock Analysis, Pergamon Press, Oxford, 2nd edn., 1975.
2. Handbook of Geochemistry, ed. K. H. Wedephol, Springer-Verlag, Berlin, 3rd edn., 1978, vol. II.
3. R. D. Reeves , and R. R.Brooks, Trace Element Analysis of Geological Materials, Wiley, New York, 1978.
4. Z. Sulcek , and P.Povondra, Decomposition in Inorganic Analysis, CRC Press, Florida, 1989.
5. J. C. van Loon , Analytical Atomic Absorption Spectroscopy Selected Methods, Academic Press, New York, 1980.