1. Douglas , Kevin. S. John Weir 2006 HCR-20 Violence Risk Assessment Scheme: Overview and Annotated Bibliography (with supplement, current up to January 12, 2006) http://www.violence-risk.com/hcr20annotated.pdf
2. Federal Sentencing Commission Federal Sentencing Guidelines, Ch. 4 (Criminal History and Criminal Livelihood), Part A (Criminal History) http://www.ussc.gov/2004guid/CHAP4.htm 2007