
https://www.instituteforgovernment.org.uk/sites/default/files/publications/IfG_Brexit_customs_WEB.pdf

https://www.publications.parliament.uk/pa/ld201617/ldselect/ldeucom/169/169.pdf

http://www.guengl.eu/news/article/eu-citizens-rights-and-status-of-north-of-ireland-must-be-prioritised-in-br