J.C. Barnes, Kevin M. Beaver, Brian B. Boutwell Plos One http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0070807#pone-0070807-g001 2013 Date Sat, 06/14/2014 - 03:04 PM Research Types Gene X Environment Interaction Gun Carrying Gun Ownership Kevin M. Beaver Terrorism