https://www.nato.int/nato_static_fl2014/assets/pdf/2021/6/pdf/210611-pr-2021-094-en.pdf
https://www.cesifo-group.de/DocDL/ifoDD_18-01_03-09_Ochsner.pdf
https://futuros.gob.es/sites/default/files/2023-09/RESILIENTEU2030.pdf
https://www.crisisgroup.org/europe-central-asia/eastern-europe/ukraine/responding-new-crisis-ukraines-borders