https://blogs.lse.ac.uk/brexit/2019/10/15/the-curve-of-inequality-and-the-brexit-way/
https://www.smmt.co.uk/wp-content/uploads/sites/2/1207-SMMT-position-on-UK-Brexit-negotiations.pdf
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/650455/customs_bill_white_paper_print.pdf
https://www.ifs.org.uk/publications/10302