https://blogs.lse.ac.uk/brexit/2019/04/15/brexit-lessons-from-the-silesian-backstop-of-1919-25/
https://cerre.eu/wp-content/uploads/2024/01/CERRE.BOOK_.DMA_.17JAN.pdf
https://ec.europa.eu/commission/publications/position-paper-transmitted-eu27-ongoing-police-and-judicial-cooperation-criminal-matters_en
http://www.parliament.uk/documents/commons-committees/Exiting-the-European-Union/17-19/Cross-Whitehall-briefing/EU-Exit-Analysis-Cross-Whitehall-Briefing.pdf