http://www.unep.or.jp/Ietc/Publications/Water_Sanitation/ponds_and_wetlands/index.asp
[Accessed: 24.02.2010]
Manual and supporting information by the UN environmental programme, providing information for designers, builders and operators on artificially constructed wetlands and waste stabilization ponds. The supporting information includes a standard systems approach which can be adopted universally; the theoretical background on the biological, chemical and physical processes of each method, the current state of the technology and technical knowledge on how to design, operate and maintain them; and theoretical knowledge on how best the models may be used to describe the systems.