1. Working processes of cyclic-action machinery for soil deformation. Part I;Spektor;J. Terramechanics,1983
2. Oscillation of tillage implements;Gunn;Agric. Engng.,1955
3. Experimental data on the effect of oscillation on the cutting resistance of soil;Shkurenko,1958
4. Grubber mit Schwingenden Werkzeugen;Eggenmuller;Grundl. Landtech.,1959
5. Measurements of the load resistance of the oscillating sub-soiler;Tetsuka;J. Soc. Agr. Mach., Japan,1962