https://blogs.sussex.ac.uk/uktpo/2017/06/12/disentangling-brexit-trade-politics-and-policies/
https://www.theguardian.com/politics/2018/jul/18/dairy-products-may-become-luxuries-after-uk-leaves-eu
http://www.guengl.eu/uploads/news-documents/Working_paper_Border_controls_on_cross_border_trade_in_goods.pdf