https://www.opendemocracy.net/en/beyond-trafficking-and-slavery/exploitation-rule-not-exception/
http://publications.iom.int/system/files/pdf/wmr_2018_en.pdf
http://library.fes.de/pdf-files/bueros/budapest/15322-20190505.pdf
https://ukandeu.ac.uk/trade-migration-and-brexit/