1. Abeels, P., 1989. Tire testing: automatic recording of the tyre deformability. Paper-American Society of Agricultural Engineers (USA).
2. ASABE, 2009. ANSI/ASAE S296.5 DEC2003(R2009) Standard. General Terminology for Traction of Agricultural Traction and Transport Devices and Vehicles. ASABE. St. Joseph, Mich. USA.
3. ASTM D 2487-83., 1985. Classification of soils for engineering purposes. American Society for Testing and Materials: Annual Book of ASTM Standards. pp. 395–408.
4. Effect of the number of tractor passes on soil rut depth and compaction in two tillage regimes;Botta;Soil Tillage Res.,2009
5. Brixius, W., 1987. Traction prediction equations for bias ply tires. ASAE paper. 87–1622: 8pp.