https://ippedico.github.io/website/ABIP_entrepreneurship_drain.pdf
https://countercurrents.org/2021/10/heroes-or-parasites-europes-self-serving-politics-on-refugees/
http://www.cesifo-group.de/ifoHome/publications/working-papers/CESifoWP/CESifoWPdetails?wp_num=6441&CESifoWP.search=+
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