
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/650455/customs_bill_white_paper_print.pdf

https://www.gov.uk/government/news/david-davis-opening-remarks-at-the-start-of-the-fourth-round-of-eu-exit-negotiations

http://www.europarl.europa.eu/cmsdata/115748/IPOL_IDA(2017)583130_EN.pdf