1. Inorganic forms of nitrogen;Bremner,1965
2. Eutrophication of taihu lake and pollution from agricultural non-point sources in lake Taihu Basin;Cheng;Journal of Agro-Environment Science,2005
3. An estimation and evaluation of non-point source (NPS) pollution in the Yellow River Basin;Cheng;Acta Scientiae Circum Stantiae,2006
4. Dong Q. 2011. Non-point source pollution of nitrogenand phosphorus burthen in Benghe watershed of the Yimeng Mountanous, Shandong Province. MSc thesis. Shandong Agriculture Univeristy, China. (in Chinese)