https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/899991/200713_BPDG_-_Border_Operating_Model_FINAL_1320_edit.pdf
http://www.nhsconfed.org/-/media/Confederation/Files/public-access/Securing-the-future.pdf?dl=1
http://www.cesifo-group.de/ifoHome/publications/working-papers/CESifoWP/CESifoWPdetails?wp_num=6438&CESifoWP.search=+