1. Water Supply and Sanitationhttp://go.worldbank.org/GJ7BOASPG0
2. Progress on Drinking Water and Sanitation: Special Focus on Sanitation,2008
3. Prospects: The 2006 Revision,2006
4. Engineers Without Borders—USAhttp://www.ewb-usa.org
5. Village empowerment: service-learning with continuity;Duffy;International Journal of Service Learning in Engineering,2008