1. Cation-exchange groupings in the soil organic fraction;Broadbent;Soil Sci.,1952
2. Physico-chemical investigation of humic acid;Burges,1960
3. Humic acid investigations, 2. Studies in the fractionation of humic acids;Coulson;J. Soil Sci.,1959
4. Role of humic acids in concentrating rare elements in soils;Drozdova;Soviet Soil Sci.,1968
5. The chemistry of soil humic substances;Dubach;Soils Fertilizers,1963