https://www.nao.org.uk/wp-content/uploads/2017/07/The-Customs-Declaration-Service.pdf
https://publications.parliament.uk/pa/bills/cbill/2017-2019/0005/18005.pdf
http://sydneydemocracynetwork.org/article-brexit-yes-will-suffer-well/
http://europa.eu/rapid/press-release_MEMO-17-2001_en.htm