1. Alloway, B.(1995) Heavy Metals in Soils. Glasgow : Blackie Academic and Professional.
2. Bergmann, W.(1988) Ernährungsstörungen bei Kulturpflanzen. Jena : VEB Gustav Fischer Verlag.
3. Buzás, I.(1988) Methods of Soil Analysis. Budapest (in Hungarian) : Agricultural Publ..
4. Chaminade, R. (1960) Experimentation en petits vases de vegetation types d'essais pour tester l'efficacite des engrais humiques Annales Agronomiques, 2, pp. 121 - 131.
5. Csathó, P.(1994) Heavy Metal Pollution of Environment and Agricultural Production. Budapest : Research Institute for Soil Science and Agricultural Chemistry of the Hungarian Academy of Sciences.