http://www.transparency.org/news/feature/europe_and_central_asia_an_overall_stagnation
https://www.bundesfinanzministerium.de/Content/DE/Downloads/Broschueren_Bestellservice/2019-08-08-die-wichtigsten-steuern-im-internationalen-vergleich-2018-ausgabe-2019.pdf?__blob=publicationFile&v=5
https://www.linkiesta.it/2020/05/macron-merkel-piano-iniziativa-500-miliardi/
https://www.politico.eu/article/christine-lagarde-profile-european-central-bank/