https://www.gov.uk/government/news/programme-for-fourth-round-of-uk-eu-article-50-negotiations
http://www.conservativehome.com/platform/2017/05/neale-richmond-no-deal-between-britain-and-the-eu-would-be-a-disaster-for-ireland.html
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/695321/An_inspection_of_exit_checks.pdf
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/397079/Scotland_EnduringSettlement_acc.pdf