1. Anon. Energy and the environment, e.water 16 April, Issue No. 140, 1999.
2. Barrett JL. An examination of the whole costs of introducing advanced wastewater treatment at Cromer sewage treatment works on the north Norfolk Coast. MSc. Thesis, Imperial College, London, 1998:122.
3. The coming spaceship Earth;Boulding,1992
4. Ecobilan. Tools for environmental analysis and management. Publicity literature, 1999.
5. The life-cycle analysis of small-scale sewage treatment processes;Emmerson;J Chart Inst Water Environ Manage,1995