5Anon. North sea quality status report[R]. London, Oslo and Paris Commissions, 1993. 132.
6Steer D, Fraser L, Boddyc J, et al. Efficiency of small constructed wetlands for subsurface treatment of single-family domestic effluent[J]. Ecological Engineering, 2002, 18: 429-440.
8Gustafson A, Fleischer S, Joelsson A. A catchment-oriented and cost-effective policy for water protection[J]. Ecological Engineering, 2000,14: 419-427.
9Maurizio B, Elisa B. Abatement of NO3-N concentration in agricultural waters by narrow buffer strips[J]. Environmental Pollution, 2002,117 : 165- 168.