https://publications.parliament.uk/pa/cm201719/cmselect/cmworpen/848/848.pdf
https://www.open-britain.co.uk/new_research_trade_deals_with_five_key_countries_could_take_26_years_to_negotiate
http://data.parliament.uk/writtenevidence/committeeevidence.svc/evidencedocument/treasury-committee/the-uks-economic-relationship-with-the-european-union/oral/72053.html