
http://www.lisbon-treaty.org/wcm/the-lisbon-treaty/treaty-on-european-union-and-comments/title-1-common-provisions/7-article-7.html

https://www.eia.gov/energyexplained/us-energy-facts/imports-and-exports.php

https://wiiw.ac.at/keeping-friends-closer-why-the-eu-should-address-new-geoeconomic-realities-and-get-its-neighbours-back-in-the-fold-dlp-6487.pdf