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

https://corporateeurope.org/power-lobbies/2017/12/big-business-brexit-corporate-interests-still-dominate-brexit-and-trade

http://ukandeu.ac.uk/for-the-third-time-we-surveyed-mps-on-their-attitude-to-brexit-and-the-results-were-fascinating/