http://fedtrust.co.uk/views-from-the-federal-trust/free-movement-and-migration/
https://www.chba.org.uk/for-members/library/overseas-seminars/the-status-of-gibraltar-under-eu-law
https://ukandeu.ac.uk/wp-content/uploads/2020/05/UKICE-Post-Brexit-Gov-NI-Report.pdf