https://rusi.org/sites/default/files/newsbrief_37.3_elliott.pdf
https://bdi.eu/media/user_upload/20171005_Pressemitteilung_Brexit.pdf
https://www.gov.uk/guidance/status-of-eu-nationals-in-the-uk-what-you-need-to-know
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/677268/Letter_to_Business_Leaders__1_.pdf