https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/680366/Technical_Note_-_International_Agreements_in_the_Implementation_Period_-_CLEAN.pdf
http://www.strengthentheeuro.eu/fileadmin/files/user_upload/EZ_flashlight_europe_2017_05_ENG.pdf
https://www.instituteforgovernment.org.uk/sites/default/files/publications/IfG_views-eu-27-v5_WEB.pdf