
https://www.nakedcapitalism.com/2018/02/another-brexit-mess-grandfathering-existing-free-trade-agreements-looks-unlikely.html

https://www.piie.com/sites/default/files/2023-04/pb23-3.pdf

https://blogs.lse.ac.uk/brexit/2021/01/11/article-16-of-the-ireland-northern-ireland-protocol-offers-no-quick-fix/