1. Proceedings and Papers of the First International Congress of Soil Science;American Organizing Committee,1928
2. Symposium on tropical soil resources,1963
3. A new system of soil classification;Bear;Soil Sci.,1963
4. The problem of soil erosion in the United States;Bennett,1928
5. A new technique in soil mapping;Bushnell;Am. Soil Surv. Assoc., Bull.,1932