
https://ec.europa.eu/commission/publications/position-paper-transmitted-eu27-ongoing-police-and-judicial-cooperation-criminal-matters_en

https://www.gov.uk/government/news/pms-open-letter-to-eu-citizens-in-the-uk

http://www.bertelsmann-stiftung.de/fileadmin/files/Projekte/Migration_fair_gestalten/IB_Study_MixedMigration2017_ENG.pdf