1. A new hand-held recording penetrometer for soil studies;Andersson;J. Soil Sci.,1980
2. Soil compaction by the tractor in spring and its effect on soil porosity;Aura;J. Sci. Agric. Soc. Finland,1983
3. Persistence of subsoil compaction in a mollisol;Blake;J. Soil Sci. Soc. Am.,1976
4. Soil compaction—a severe problem in Finnish agriculture;Elonen;Swedish University of Agricultural Sciences, reports from the Division of Soil Management, Uppsala,1980
5. Swedish experiments on subsoil compaction by vehicles with high axle load;Håkansson;soil Use Manage.,1985