
http://news.sky.com/story/theresa-may-theres-no-economic-case-for-breaking-up-the-uk-10787816

https://www.theguardian.com/politics/2017/sep/04/uk-trade-deals-after-brexit-theresa-may-eu

https://ec.europa.eu/commission/sites/beta-political/files/customs_controls_0.pdf