https://www.zora.uzh.ch/id/eprint/168933/1/From_welfare_to_warfare_Voth.pdf
https://www.opendemocracy.net/uk/looking-at-lexit/guy-aitchison/borders-open-borders-or-no-borders?utm_source=Daily+Newsletter&utm_campaign=0a51e05bcc-DAILY_NEWSLETTER_MAILCHIMP&utm_medium=email&utm_term=0_717bc5d86d-0a51e05bcc-407405485
https://www.politico.com/f/?id=00000180-874f-dd36-a38c-c74f98520000
https://www.ipg-journal.de/regionen/europa/artikel/detail/aussenpolitik-nach-wildwest-manier-4419/