1. ‘Humic Substances in Soil and Crop Sciences: Selected Readings’;Chen,1990
2. ‘Humic Substances in Terrestrial Ecosystems’;Chen,1996
3. ‘Humic Substances in Terrestrial Ecosystems’;Nardi,1996
4. ‘Soil Organic Matter and Biological Activity’;Vaughan,1985
5. ‘Soil Organic Matter and Biological Activity’;Vaughan,1985