1. Invloed van sporen op de groei en opbrengst van suikerbieten (summary in English);Alblas,1989
2. Verlassene Krumenschichten—eine Frage der Plugtiefe;Altemüller,1957
3. Nitrogen turnover by earthworms in arable plots treated with farmyard manure and slurry;Andersen,1983
4. Microstructure and stability of two sandy loam soils with different soil management;Bouma,1969
5. The Dutch Programme on Soil Ecology of Arable Farming Systems 1. Objectives, approach and preliminary results;Brussaard,1988