
https://www.nao.org.uk/wp-content/uploads/2018/01/Implementing-the-UKs-exit-from-the-European-Union-the-Deparment-for-International-Trade.pdf

https://www.euronews.com/2018/09/25/why-is-the-irish-border-issue-so-complex-euronews-answers

https://publications.parliament.uk/pa/cm201719/cmselect/cmfaff/514/514.pdf