
https://www.nao.org.uk/wp-content/uploads/2016/02/Managing-the-supply-of-NHS-clinical-staff-in-England.pdf

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/866744/CCS0120013106-001_The_UKs_Points-Based_Immigration_System_WEB_ACCESSIBLE.pdf

http://library.fes.de/pdf-files/bueros/budapest/15322-20190505.pdf