https://www.bruegel.org/wp-content/uploads/2021/10/Storms-Ahead_AGH_chp6.pdf
http://www.cepii.fr/PDF_PUB/pb/2021/pb2021-36.pdf
https://www.nytimes.com/2019/06/06/world/europe/us-defense-spending-nato.html
https://www.friendsofeurope.org/insights/critical-thinking-navigating-the-new-world-order-reflection-on-the-nato-summit-in-washington/