https://www.gov.uk/government/news/programme-for-fourth-round-of-uk-eu-article-50-negotiations
https://publications.parliament.uk/pa/cm201719/cmselect/cmhaff/421/421.pdf
http://www.iata.org/whatwedo/Documents/economics/impact_of_brexit.pdf
https://www.gov.uk/government/news/joint-article-a-deep-and-special-partnership