1. Humic substances in Soil and Crop Sciences-Selected Readings;MacCarthey,1990
2. Humic Substances in the Global Environment and Implications on Human Healt;Tombacz,1994
3. Humic Substances and Their Role in the Environmen;Weber,1988
4. Humic Substances in the Environment;Schnitzer,1972
5. Reviews in Acquatic Sciences;Francois,1990