https://www.congress.gov/117/plaws/publ169/PLAW-117publ169.pdf
https://www.eca.europa.eu/Lists/ECADocuments/REW19_09/REW_EU-defence_EN.pdf
https://www.linkiesta.it/2020/05/macron-merkel-piano-iniziativa-500-miliardi/
https://www.gsb.stanford.edu/gsb-box/route-download/621098