https://blogs.lse.ac.uk/brexit/2020/02/21/migration-how-scotland-hoped-to-do-things-differently/
https://www.tandfonline.com/doi/full/10.1080/13511610.2021.1968355
https://www.llri.lt/wp-content/uploads/2018/06/Labour-Migration_3.pdf
http://researchbriefings.files.parliament.uk/documents/CBP-7840/CBP-7840.pdf