https://publications.parliament.uk/pa/cm201719/cmselect/cmpubacc/401/401.pdf
https://blogs.lse.ac.uk/brexit/2019/04/15/brexit-lessons-from-the-silesian-backstop-of-1919-25/
http://www.oliverwyman.com/content/dam/oliver-wyman/v2/publications/2018/march/Oliver-Wyman_Clifford-Chance-The-Red-Tape-Cost-of-Brexit.pdf
https://sosapadilla.github.io/files/papers/Bianchi_Sosa-Padilla_PP.pdf