1. Biological Process Design for Wastewater Treatment;Benefield,1980
2. The alternative to aeration;Booth,1983
3. The cost of sewage treatment;Bradley;Wat. Pollut. Control,1969
4. Economic aspects of sewage works design;Cupit;Wat. Pollut. Control,1969
5. Biological wastewater treatment under the influence of pressure;Ellis;J. IWEM,1992