http://www.bms.com/ehs/issues/data/conser.html
http://www.waterwheelfactory.com/
http://ga.water.usgs.gov/edu/wuhy.html
http://edis.ifas.ufl.edu/AE021
http://hyperphysics.phy-astr.gsu.edu/Hbase/thermo/houseenergy.html
http://www.eia.doe.gov/kids/energyfacts/sources/renewable/water.html#hydroelectricity
http://www.stevenashley.info/2008/02/hydrogen-from-water-with-solar-energy.html.