1. Soil loads on plough bodies, Part II;Rogers,1956
2. The soil forces acting on the body and on the disc coulter of a plough;Tanner;J. agric. Engng Res.,1963
3. The influence of speed on the performance characteristics of implements;McKibben,1952
4. Untersuchungen über die Form von Pflugkörpern bei erhöhter Fahrgeschwindigkeit;Söhne;Grundl. Landtech. 11,1959