https://bdi.eu/media/pressecenter/#/artikel/news/brexit-wirft-seine-schatten-voraus/
http://blogs.lse.ac.uk/brexit/2017/12/05/a-high-risk-game-of-chicken-is-being-played-over-the-irish-border/
https://www.iwh-halle.de/fileadmin/user_upload/publications/iwh_discussion_papers/iwh-discussion-paper_2019-04_Brautzsch_Holtemoeller.pdf
http://www.europarl.europa.eu/cmsdata/115748/IPOL_IDA(2017)583130_EN.pdf