1. National Center for Injury Prevention and Control. http://webappa.cdc.gov/sasweb/ncipc/leadcaus10.html 2010
2. Centers for Disease Control and Prevention. http://www.cdc.gov/ncipc/dvp/YVP 2009
3. School associated student homicides-United States, 1992-2006.;Centers for Disease Control and Prevention.;Morb Mortal Wkly Rep,2008
4. National Center for Educational Statistics. http://nces.ed.gov/programs/crimeindicators/crimeindicators2007 2008