1. P. Bokk (1984 ) Methods of decomposition in analytical chemistry . Mir (Moscow), 432 pp.
2. Catalogue reference samples of natural environmental media (2001 ) Russian Academy of Sciences, Siberian Branch , Institute of Geochemistry, 50 pp (in Russian).
3. Certificate of geochemical standard reference materials (1986 ) Institute of Geophysical and Geochemical Exploration (Langfang, Hebei, China), 25 pp.
4. A.G. Darnley, A. Bjorklund, and B. Bolviken andeight others (1995 ) Recommendation for international geochemical mapping . Final report of IGCP Project 259. UNESCO Publishing (Ottawa), 121 pp.