1. W.H. Rulkens, J.W. Assink: Extraction as a method for cleaning contaminated soil: possibilities, problems and research; Proc. Conf. Management Uncontrolled Hazardous Waste Sites, Washington DC 1984 (Hazardous Materials Control Research Institute, Silver Spring, Maryland, 1984 ) pp 576–583.
2. M.A. Smith (edit.): Contaminated Land: Reclamation and Treatment. Plenum Press, New York and London, 1985.
3. Handboek Bodemsaneringstechnieken (Handbook Techniques for Remedial Action), Staatsuitgeverij, The Hague, 1983.
4. Personal communication with B. Hilberts (Heijmans Milieutechniek B.V., P.O. box 2, 5240 BB Rosmalen, Netherlands).
5. Personal communication with C.J. Muntinga (HWZ Bodemsanering B.V., Vanadiumweg 5, 3812 PX Amersfoort, Netherlands).