https://www.euronews.com/2018/09/25/why-is-the-irish-border-issue-so-complex-euronews-answers
https://publications.parliament.uk/pa/cm201719/cmselect/cmhaff/421/421.pdf
https://blogs.lse.ac.uk/brexit/2019/10/23/long-read-the-makings-of-brexit-and-the-road-ahead/
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/682894/Draft_Text_for_Discussion_-_Implementation_Period__1_.pdf