https://ec.europa.eu/commission/sites/beta-political/files/customs_controls_0.pdf
https://trade.ec.europa.eu/doclib/docs/2017/december/tradoc_156474.pdf
http://ukandeu.ac.uk/wp-content/uploads/2017/06/One-year-on.pdf
https://ahdb.org.uk/documents/Horizon_meatanddairy_Sept2017.pdf