https://researchbriefings.files.parliament.uk/documents/CBP-7212/CBP-7212.pdf
https://www.iod.com/Portals/0/PDFs/Campaigns%20and%20Reports/Europe%20and%20trade/Business-of-Brexit.pdf?ver=2017-05-22-090428-150
https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef1710en.pdf
https://www.project-syndicate.org/commentary/poland-hungary-elections-2019-by-slawomir-sierakowski-2019-10