dylan klebold sources Background Sources: Books: Cullen, D. (2009). Columbine. Twelve. Kass, J. (2014). Columbine: A True Crime Story. Conundrum Press. Klebold, Sue. (2016). A Mother’s Reckoning: Living in the Aftermath of Tragedy. Crown Publishers. Narrative Source: https://schoolshooters.info/dylan-klebold