Research paper

https://katu.com/news/local/judge-finds-trimet-transit-police-violated-max-riders-constitutional-rights

https://www.wweek.com/news/2017/06/07/the-double-slaying-on-the-max-intensifies-debate-over-trimets-plans-to-increase-transit-police/

https://www.wweek.com/news/city/2017/08/03/max-ridership-drops-slightly-in-month-after-portland-slayings-but-cause-of-decline-remains-elusive/

https://www.wweek.com/news/2017/06/07/the-double-slaying-on-the-max-intensifies-debate-over-trimets-plans-to-increase-transit-police/

http://www.oregonlive.com/commuting/index.ssf/2018/01/trimet_to_hire_portland_patrol.html

https://www.thoughtco.com/how-safe-is-public-transportation-2798815

https://mta.maryland.gov/transitblog/ten-ways-be-safe-and-feel-safe-public-transportation-4

https://www.kptv.com/news/trimet-users-happy-with-service-but-concerned-about-safety/article_165958fc-c5d9-52b0-8618-e58878a8f7d5.html

https://www.portlandoregon.gov/police/article/529197

https://search.library.pdx.edu/primo-explore/fulldisplay?docid=TN_gale_ofa321553145&context=PC&vid=PSU&search_scope=all&tab=default_tab&lang=en_US

https://trimet.org/meetings/board/pdfs/2017-07-26/2016-security.pdf (must use this )