https://publications.parliament.uk/pa/ld201719/ldselect/ldeucom/129/129.pdf
https://www.rand.org/pubs/research_reports/RR2200.html
https://visual.ons.gov.uk/commonwealth-trade-in-focus-as-uk-prepares-for-brexit/
https://committees.parliament.uk/publications/30492/documents/175947/default/