
https://www.cesifo-group.de/DocDL/ifoDD_18-01_03-09_Ochsner.pdf

http://openeurope.org.uk/today/blog/will-brexit-ground-flights-europe/

https://www.spectator.co.uk/article/full-text-top-uk-brexit-negotiator-david-frost-on-his-plans-for-an-eu-trade-deal