1. The Last Drop: Confronting the possibility of a global catastrophehttp://www.newyorker.com/archive/2006/10/23/061023fa_fact1
2. Human appropriation of renewable fresh water;Postel;Science,1996
3. A Precious Resource: Investing in the fate of fresh waterhttp://www.allbusiness.com/banking-finance/financial-markets-investing/7304522-1.html
4. http://whqlibdoc.who.int/publications/2008/ 9789241596435_eng.pdf