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

http://carnegieeurope.eu/2017/06/15/bringing-brexit-back-to-reality-pub-71262

https://www.bloomberg.com/opinion/articles/2020-12-18/britain-and-europe-s-fish-fight-reveals-ultimate-brexit-truths