https://www.smmt.co.uk/wp-content/uploads/sites/2/1207-SMMT-position-on-UK-Brexit-negotiations.pdf
http://www.ilo.org/wcmsp5/groups/public/—dgreports/—dcomm/—publ/documents/publication/wcms_490959.pdf
https://www.hamiltonproject.org/assets/files/UnionsEA_Web_8.19.pdf