https://www.esri.ie/system/files/publications/WP677_0.pdf
http://www.bankofengland.co.uk/publications/Documents/speeches/2017/speech1001.pdf
https://www.ilo.org/wcmsp5/groups/public/—ed_norm/—ipec/documents/publication/wcms_854733.pdf
http://neilcummins.com/tie_cog.pdf