
http://www.epc.eu/documents/uploads/pub_7788_whatnowoptionsforbrexit.pdf?cmpid=BBBXT061617_BIZ&utm_medium=email&utm_source=newsletter&utm_term=170616&utm_campaign=brexit

https://publications.parliament.uk/pa/cm201719/cmselect/cmfaff/780/780.pdf

https://www.instituteforgovernment.org.uk/sites/default/files/publications/IfG_Brexit_customs_WEB.pdf