https://ukandeu.ac.uk/wp-content/uploads/2021/03/Freeports.pdf
http://www.europarl.europa.eu/cmsdata/115748/IPOL_IDA(2017)583130_EN.pdf
https://www.instituteforgovernment.org.uk/sites/default/files/publications/5704%20IFG%20-%20Frictionless%20Trade%20Web.pdf
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/699106/UK_position_paper_on_future_of_cohesion_policy_.pdf