1. Allott, N., Brennan, M., Mills, P. and Eacrett, A.: 1993, In: Ecological effects of afforestion. C Watkins (ed.), 165?177. C.A.B. International, Wallingford, UK.
2. Anderson, H.A., Peacock, S., Berg, A. and Ferrier, R.C.: 1995, Wat. Air Soil Pol., (This volume).
3. Barrow, N.J.: 1987, Reactions with variable charge soils. Klewer Academic Publishers, Dordrecht, Netherlands.
4. Curtin, D. and Syers, J.K.: 1990, J. Soil Sci., 41, 433?442.
5. Harriman, R. and Wells, D.E.W.: 1985, J. Wat. Poll. Cont. Fed., 84, 215?224.