http://www.aircommandrockets.com/flying_higher.htm
http://www.sciencetoymaker.org/waterRocket/buildWaterRocketLauncher.htm
https://www.youtube.com/watch?v=1t663D_gErg
http://www.waterrocketmanual.com/how_they_work.htm
http://www.txsnapper.eezway.org/txsnapper/tips.html
http://www.npl.co.uk/upload/pdf/wr_booklet_print.pdf
The entire details for water rocket can be downloaded here