Recent research related to parole.
https://www.prisonpolicy.org/reports/longsentences.html?fbclid=IwAR2W-fryH-e8_tOaOmrsn5BTCakY9E4WCUYxavcTGyZXaE7qLcF5gwDqF3Y
[...]
https://www.sentencingproject.org/wp-content/uploads/2018/03/32-lifer-parole-policies.pdf
[...]
http://www.law.nyu.edu/sites/default/files/ecm_pro_062016.pdf
[...]
https://scholarship.law.umn.edu/cgi/viewcontent.cgi?article=1535&context=faculty_articles
[...]
https://academicworks.cuny.edu/cgi/viewcontent.cgi?article=1430&context=clr
[...]
https://www.sentencingproject.org/wp-content/uploads/2018/08/Decarceration-Strategies.pdf?eType=EmailBlastContent&eId=a761a9fc-178d-4700-8421-c1e0b3047a50
[...]
http://centerforjustice.columbia.edu/files/2015/10/AgingInPrison_FINAL_web.pdf
[...]