https://blogs.sussex.ac.uk/uktpo/2018/12/17/organising-the-second-referendum/
https://docs.iza.org/dp16728.pdf
http://www.migrationobservatory.ox.ac.uk/resources/reports/unsettled-status-which-eu-citizens-are-at-risk-of-failing-to-secure-their-rights-after-brexit/
https://www.kcl.ac.uk/sspp/policy-institute/publications/What-sort-of-Brexit-do-the-British-people-want.pdf