1. Akerkar, R. A., & Sajja, P. S. (2009). Knowledge-based systems. Sudbury: Jones & Bartlett Publishers.
2. APHA, AWWA, & WEF. (2005). Standard methods for the examination of water and wastewater (21st ed.) Washington, DC: American Public Health Association/American Water Works Association.
3. Beccari, M., Passino, R., Ramadori, R., & Vismara, R. (1997). Rimozione di azoto e fosforo dai liquami, ed. Italia: Hoepli ISBN 88-203-1968-3 (in Italian).
4. Belchior, C. A. C., Araújo, R. A. M., & Landeck, J. A. C. (2012). Dissolved oxygen control of the activated sludge wastewater treatment process using stable adaptive fuzzy control. Computers and Chemical Engineering, 37, 152–162.
5. Benetto, E., Dujet, C., & Rousseaux, P. (2008). Integrating fuzzy multicriteria analysis and uncertainty evaluation in life cycle assessment. Environmental Modelling and Software, 23(12), 1461–1467.