http://fedtrust.co.uk/views-from-the-federal-trust/free-movement-and-migration/
https://www.gov.uk/government/news/joint-article-a-deep-and-special-partnership
https://rusi.org/sites/default/files/newsbrief_37.3_elliott.pdf
https://bdi.eu/media/pressecenter/#/artikel/news/brexit-wirft-seine-schatten-voraus/