http://data.parliament.uk/writtenevidence/committeeevidence.svc/evidencedocument/treasury-committee/the-uks-economic-relationship-with-the-european-union/oral/72053.html
http://www.guengl.eu/uploads/news-documents/Working_paper_Border_controls_on_cross_border_trade_in_goods.pdf
https://ukandeu.ac.uk/post-global-britain-a-new-normal-in-uk-foreign-policy/?mc_cid=a36ff76330&mc_eid=815b1928ec