https://publications.parliament.uk/pa/ld201719/ldselect/ldconst/69/69.pdf
http://www.europarl.europa.eu/cmsdata/115748/IPOL_IDA(2017)583130_EN.pdf
https://ukandeu.ac.uk/boris-johnsons-brexit-deal-whats-in-it-and-how-is-it-different-to-theresa-mays-version/