1. Continuous cropping of peanuts at Katherine, N.T.;Arndt;Tech. Pap. 16, Div. Ld Res. reg. Surv. CSIRO,1961
2. Soil structure;Russell;Tech. Commun. 37, imp. Bur. Soil Sci.,1938
3. Aggregation of soil;Vilensky;USSR Acad. Sci., Moscow,1945
4. Tillage practices and mechanization;Hawkins;Neth. J. agric. Sci,1963
5. Surface soil cloddiness in relation to soil density at time of tillage;Lyles;Soil Sci.,1961