https://www.bruegel.org/wp-content/uploads/2022/02/PC-04.pdf
https://www.nao.org.uk/wp-content/uploads/2018/01/Implementing-the-UKs-exit-from-the-European-Union-the-Deparment-for-International-Trade.pdf
https://www.cer.eu/sites/default/files/insight_SL_5.11.19_2.pdf
https://ecipe.org/wp-content/uploads/2024/02/ECI_OccasionalPaper_01-2024_LY06.pdf