https://knowledge.wharton.upenn.edu/article/us-companies-react-tariffs/?utm_source=kw_newsletter&utm_medium=email&utm_campaign=2019-06-25
https://blogs.lse.ac.uk/brexit/2019/04/15/brexit-lessons-from-the-silesian-backstop-of-1919-25/
https://www.publications.parliament.uk/pa/cm201617/cmselect/cmbeis/909/909.pdf