1. ( Murders of Passion, Execution Delays, and the Deterrence of Capital Punishment Joanna M. Shepherd* August, 2003 Clemson University )
2. (The Impact of Incentives on Human Behavior, Can we make it dissapear? The Case of the Death Penalty, by Nanci Mocan)
3. ( Ehrlich, Isaac. "The Deterrent Effect of Capital Punishment: A Question of Life and Death," The American Economic Review, Vol. 65, No. 3. (1975), pp. 397-417.)
4. ( http://www.heritage.org/research/testimony/the-death-penalty-deters-crime-and-saves-lives )
5. (Shepherd, Joanna M. "Murders of Passion, Execution Delays, and the Deterrence of Capital Punishment," Clemson University Working Paper, (2003). )
6. (Statistical Evidence on Capital Punishment and the Deterrence of Homicide by Paul Rubin)
7. ( http://www.judiciary.house.gov/legacy/shepherd042104.pdf )
8. ( http://www.nationalreview.com/article/377488/shaky-case-against-death-penalty-john-r-lott-jr )
9. ( http://www.cato-unbound.org/2012/03/07/joshua-marquis/rightful-convictions )
10. ( http://america.aljazeera.com/articles/2013/9/30/report-finds-nycinmatecostalmostasmuchasivyleaguetuition.html )
11. ( http://www.bbc.com/news/uk-19395427 )