http://www.consilium.europa.eu/en/press/press-releases/2017/04/29-euco-brexit-guidelines/
http://blogs.lse.ac.uk/brexit/2018/05/15/switzerland-wanted-more-immigration-controls-but-economic-self-interest-will-probably-prevail/
https://www.destatis.de/DE/PresseService/Presse/Pressemitteilungen/2017/08/PD17_261_12511pdf.pdf?__blob=publicationFile
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1036046/An_Inspection_of_UK_Visas_and_Immigration_Front_End_Services__August_2020_to_June_2021.pdf