http://en.wikipedia.org/wiki/Gamma_ray

http://www.epa.gov/radiation/understand/gamma.html

http://www.ndt-ed.org/EducationResources/CommunityCollege/Radiography/Physics/gamma.htm

http://www.newworldencyclopedia.org/entry/Gamma_ray

http://www.answers.com/topic/gamma-ray

http://www.wordiq.com/definition/Gamma_ray

http://www.ndt-ed.org/EducationResources/CommunityCollege/RadiationSafety/introduction/gamma.htm

http://www.hps.org/publicinformation/ate/q386.html

http://en.wikipedia.org/wiki/Radiological

http://www.epa.gov/narel/radnet/glossary.html