1. A.U.C.J. van Beurden, A.A. van der Veen, Areal units for environmental decision support, revisited, Proceedings, Joint European Conf. Exhibition on Geograph. Information, Vol. 1, The Hague, Netherlands, AKM Messen, Basel, 1995, pp. 292–297.
2. RIVM, Nationale Milieubalans, Samson, Alphen aan de Rijn, 1996, p. 142.
3. R.F. Beerling, S.L. Kwee, J.J.A. Mooij, C.A. van Peursen, Inleiding tot de wetenschapsleer, Bijleveld, Utrecht, 1970.
4. M.F. Goodchild, The state of GIS for environmental problem-solving, in: M.F. Goodchild (Ed.), Environmental modelling with GIS, Oxford Univ. Press, New York, 1993.
5. R. Janssen, Multi-objective decision support for environmental problems, Doctorate Thesis, Free Univ. of Amsterdam, Elinkwijk, Utrecht, 1992, p. 240.