1. Mitchell, R.L., in Chemistry of the Soil, 2nd edn., ed. Bear, F.E. Reinhold, New York (1964), 320–268.
2. Krauskopf, K.B., Introduction to Geochemistry, McGraw-Hill, New York (1967).
3. Rose, A.W., Hawkes, H.E. and Webb, J.S., Geochemistry in Mineral Exploration, 2nd edn. Academic Press, London (1979).
4. Kim, K.W. and Thornton I., Environ. Geochem. and Health 15, (1993), 119–133.
5. Bowen, H.J.M., Environmental Chemistry of the Elements. Academic Press, London (1979).