1. Rio+20 from a Water Perspectivehttp://www.unwater.org/news-events/news-details/en/c/207616/
2. Our Common Future: Report of the World Commission on Environment and Development,1987
3. Water Resources Sustainability;Mays,2006
4. Sustainability Criteria for Water Resource Systems;Loucks,1999
5. Sustainability of Ground–Water Resources;Alley,1999