https://publications.parliament.uk/pa/cm201719/cmselect/cmhaff/961/961.pdf
http://www.unhcr.org/4963237411.pdf
https://read.oecd-ilibrary.org/social-issues-migration-health/international-migration-outlook-2018_migr_outlook-2018-en#page1
http://www.guengl.eu/news/article/gue-ngl-news/adoption-of-the-european-travel-information-and-authorisation-system-a-hidd
https://voxdev.org/topic/labour-markets-migration/let-their-people-come-migrants-drivers-knowledge-diffusion
https://www.crisisgroup.org/global/misery-strategy-human-cost-conflict
https://www.eurofound.europa.eu/sites/default/files/wpef17037.pdf
http://blogs.lse.ac.uk/brexit/2018/05/15/switzerland-wanted-more-immigration-controls-but-economic-self-interest-will-probably-prevail/
http://ec.europa.eu/eurostat/statistics-explained/index.php/Acquisition_of_citizenship_statistics
https://openmigration.org/en/op-ed/how-immigrants-are-saving-the-italian-economy-and-pensions/