http://www.cer.org.uk/sites/default/files/insight_js_st_9.6.17.pdf
http://cdn.budgetresponsibility.org.uk/July_2017_Fiscal_risks.pdf
https://www.gov.uk/government/news/programme-for-fourth-round-of-uk-eu-article-50-negotiations
https://publications.parliament.uk/pa/cm201719/cmselect/cmbeis/379/379.pdf