http://howto.killerhurtz.co.uk/pneumatics.htmhttp://howto.killerhurtz.co.uk/pneumatics.htm

http://www.teamonslaught.fsnet.co.uk/tech.htmhttp://www.teamonslaught.fsnet.co.uk/tech.htm

http://www.gt-electronics.freeserve.co.uk/c2/technical/technical.htmhttp://www.gt-electronics.freeserve..../technical.htm

http://www.teamdavinci.com/understanding_pneumatics.htmwww.teamdavinci.com/understanding_pneumatics.htm

Enjoy.