
https://www.nao.org.uk/wp-content/uploads/2017/07/The-Customs-Declaration-Service.pdf

https://www.ost-ausschuss.de/sites/default/files/pm_pdf/2023%2012%2006%20_%20Position%20concerning%20blockade%20on%20EU-UA%20border_final.pdf

https://researchbriefings.files.parliament.uk/documents/CBP-7212/CBP-7212.pdf