https://www.un.org/esa/population/publications/migration/migration.htm
https://ukandeu.ac.uk/what-have-we-learned-about-migration-from-the-census/?mc_cid=50b7d10115&mc_eid=815b1928ec
https://www.brookings.edu/blog/the-avenue/2017/08/03/u-s-immigration-levels-continue-to-fuel-most-community-demographic-gains/?utm_campaign=Brookings%20Brief&utm_source=hs_email&utm_medium=email&utm_content=54956018
https://www.gov.uk/guidance/status-of-eu-nationals-in-the-uk-what-you-need-to-know