https://ukandeu.ac.uk/increased-immigration-from-non-eu-countries-not-just-a-british-phenomenon/
https://theconversation.com/us-and-european-economies-depend-heavily-on-immigrants-decades-of-data-reveal-just-how-much-261508
http://library.fes.de/pdf-files/bueros/budapest/15322-20190505.pdf
https://carnegieendowment.org/politika/88202