http://www.irsd.be/website/images/livres/rmb/19/ed_19_art_16.pdf
http://www.aviationlaw.eu/wp/wp-content/uploads/2013/09/Freedoms-of-the-Air-Explained.pdf
https://www.bruegel.org/first-glance/energy-shock-which-there-no-playbook
https://www.foreignaffairs.com/western-europe/problem-child-europe