https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/637748/Future_customs_arrangements_-_a_future_partnership_paper.pdf
http://www.europarl.europa.eu/RegData/etudes/STUD/2017/602028/IPOL_STU(2017)602028_EN.pdf
https://blogs.lse.ac.uk/brexit/2020/10/01/churchill-the-european-has-been-written-out-of-history/#comments