http://europa.eu/rapid/press-release_IP-18-463_en.htm
http://www.transfrontier.eu/regions/ireland-northern-ireland/
https://visual.ons.gov.uk/commonwealth-trade-in-focus-as-uk-prepares-for-brexit/
https://www.instituteforgovernment.org.uk/sites/default/files/publications/IfG_Brexit_customs_WEB.pdf