1. Albers, R., Beck, J., Bleeker, A., van Bree, L., van Dam, J., van der Eerden, L., Freijer, J., van Hinsberg, A., Marra, M., vander Salm, C., Tonneijck, A., De Vries, W., Wesselink, L., Wortelboer, F., 2001. Evaluatie van de verzuringsdoelstellingen: de onderbouwing. National Institute of Public Health and the Environment, report no. 725501001. 200 pp.
2. Pattern Recognition with Fuzzy Objective Function Algorithms;Bezdek,1981
3. FCM: the fuzzy c-means clustering algorithm;Bezdek;Comput. Geosci.,1984
4. Changes in the carbon and nitrogen status of forest soil organic horizons between 1949/50 and 1987;Billett;Environ. Pollut.,1990
5. Forest soil chemical changes between 1949/50 and 1987;Billett;J. Soil Sci.,1990