1. Salomons, W., Van Driel, W., Kerdijk, H. and Boxma, R. Proc. Exeter Symp. Vol. 139, pp.255–269. IRAS.
2. Jackson, M.L. 1958.Soil Chem. Analysis, 498Englewood Cliffs, N.J.: Prentice Hall.
3. Engler, R.M., Brannon, J.M., Rose, J. and Bigham, G. 168th Meeting Amer. Chem. Soc. Atlantic City, N.Y. pp.17
4. Salomons, W. and Förstner, U. 1984.Metals in the Hydrocycle, 349Springer Verlag Berlin.
5. Allgemeine Mikrobiologie