https://www.cesifo.org/DocDL/cesifo1_wp7982.pdf
https://borderlex.net/2021/04/13/comment-quo-vadis-energy-charter-treaty/
https://institute.global/news/customs-and-exiting-european-union
http://www.ecb.europa.eu/pub/pdf/other/ebart201703_01.en.pdf