http://www.cer.org.uk/sites/default/files/insight_JS_9.5.17.pdf
https://www.instituteforgovernment.org.uk/sites/default/files/publications/IfG_Brexit_customs_WEB.pdf
https://www.jean-jaures.org/wp-content/uploads/2023/10/Forging_Europes_Leadership.pdf
https://www.ecfr.eu/article/commentary_european_solidarity_tracker_the_solidarity_that_always_was_there