https://www.theguardian.com/politics/2017/sep/04/uk-trade-deals-after-brexit-theresa-may-eu
https://cerre.eu/wp-content/uploads/2024/01/CERRE.BOOK_.DMA_.17JAN.pdf
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/650455/customs_bill_white_paper_print.pdf
http://blogs.lse.ac.uk/politicsandpolicy/john-mills-ge2017/