https://www.destatis.de/Europa/EN/Topic/Economy-Finance/Debt.html
https://www.omfif.org/analysis/commentary/2017/june/uk-risks-falling-behind-europe/
https://openknowledge.worldbank.org/bitstream/handle/10986/36647/What-Has-Been-the-Impact-of-COVID-19-on-Debt-Turning-a-Wave-into-a-Tsunami.pdf?sequence=1&isAllowed=y
https://www.ifo.de/DocDL/EEAG-2019-executive-summary.pdf