https://ec.europa.eu/commission/sites/beta-political/files/joint_report.pdf
https://centreonconstitutionalchange.ac.uk/sites/default/files/2021-04/Union%20at%20the%20Crossroads.pdf
https://www.rte.ie/news/analysis-and-comment/2017/1117/920981-long-read-brexit/?utm_source=POLITICO.EU&utm_campaign=693f844ad1-EMAIL_CAMPAIGN_2017_11_20&utm_medium=email&utm_term=0_10959edeb5-693f844ad1-189647205
https://publications.parliament.uk/pa/cm201719/cmselect/cmbeis/380/380.pdf