http://www.nhsconfed.org/-/media/Confederation/Files/public-access/Securing-the-future.pdf?dl=1
https://www.gov.uk/government/news/david-davis-speech-at-ubs
https://publications.parliament.uk/pa/ld5801/ldselect/ldeucom/4/4.pdf
https://ukandeu.ac.uk/long-read/the-protocol-post-brexit-northern-ireland/?mc_cid=9de7c359e6&mc_eid=815b1928ec