https://en.wikipedia.org/wiki/Solitary_confinement
https://www.theguardian.com/us-news/2016/feb/19/albert-woodfox-released-louisiana-jail-43-years-solitary-confinement
https://www.news.com.au/world/europe/robert-maudsley-prisoner-sets-record-for-longest-time-in-solitary-confinement/news-story/5d736730049cf7124d23a32076e845ed
https://en.wikipedia.org/wiki/San_Quentin_Six
https://dondivamag.com/who-is-behind-the-prison-hit-on-revolutionary-hugo-pinell/
https://www.latimes.com/local/lanow/la-me-pc-prison-investigators-name-suspects-in-prison-killing-of-hugo-pinell-20151009-story.html
https://www.globalresearch.ca/hugo-pinell-assassinated-in-california-prison-yard/5469728
www.partisandefense.org/pubs/articles/2015-09-04_pinell.html
https://www.globalresearch.ca/hugo-pinell-assassinated-in-california-prison-yard/5469728
https://sfbayview.com/2015/08/prisoners-speak-out-about-the-assassination-of-hugo-pinell/
https://www.latimes.com/local/political/la-me-slain-prisoner-hugo-pinell-was-a-target-of-prison-gangs-20150813-story.html
https://newsandletters.org/prisoners-speak-hugo-yogi-pinell/
https://www.ocregister.com/2016/10/06/lawsuit-says-california-could-have-stopped-prison-slaying/
http://www.sundiataacoli.org/i-was-one-of-the-last-ones-to-see-our-beloved-brotha-yogi-alive-1220
https://www.dailyrepublic.com/all-dr-news/opinion/letters-editor/hugo-pinell-killing-serves-justice/