http://www.europarl.europa.eu/RegData/etudes/STUD/2017/602028/IPOL_STU(2017)602028_EN.pdf
https://www.instituteforgovernment.org.uk/sites/default/files/publications/5704%20IFG%20-%20Frictionless%20Trade%20Web.pdf
http://reutersinstitute.politics.ox.ac.uk/risj-review/sympathetic-unconcerned-how-europes-media-cover-brexit
https://publiclawforeveryone.com/2017/06/10/does-the-salisbury-convention-apply-during-a-hung-parliament/