http://www.nde-ed.org/educationresources/communitycollege/radiography/introduction/history.html
http://www.slac.stanford.edu/pubs/beamline/25/2/25-2-assmus.pdf
http://inventors.about.com/od/xyzstartinventions/a/x-ray.html
www.discoveriesinmedicine.com/to-z/x-ray-machine.hmtl
http://science.howstuffworks.com/dictionary/physics-terms/xray-info2.html
http://www.slac.stanford.edu/pubs/beamline/25/2/25-2-assmus.pdf
http://inventors.about.com/od/xyzstartinventions/a/x-ray.html
www.discoveriesinmedicine.com/to-z/x-ray-machine.hmtl
http://science.howstuffworks.com/dictionary/physics-terms/xray-info2.html