1. Adams, F., 1965. Manganese. In: Black, C.A. (Ed.), Methods of Soil Analysis, Agronomy No. 9, Part 2, Chemical and Biological Properties. Madison, Wisconsin, pp. 1101–1018 (Chapter 69).
2. Behaviour of chromium in soils. III. Oxidation;Bartlett;J. Environ. Qual.,1979
3. Bartlett, R.J., Kimble, J.M., 1976. Behaviour of chromium in soils: II. Hexavalent forms. J. Environ. Qual. 5, 383–386.
4. Brooks, R.R., 1987. Serpentine and its vegetation. A multi- disciplinary approach. Ecology, Phytogeography and Physiology series, Volume 1. Dioscorides Press. Portland, Oregon.