https://www.ft.com/content/b638551a-68c3-11e7-8526-7b38dcaef614
https://hansard.parliament.uk/commons/2018-03-07/debates/65828E0C-3CC7-43AE-B5D2-B5F1B5D42A4C/EuropeanUnionCitizenship
http://fedtrust.co.uk/our-work-on-europe/there-may-be-trouble-ahead-brexit-after-the-election/
http://docs.dpaq.de/10395-0216-euco-conclusions.pdf