https://www.corriere.it/politica/22_novembre_18/di-maio-nuova-vita-sara-inviato-speciale-ue-golfo-persico-trattare-prezzo-petrolio-gas-0805b148-6720-11ed-b05a-06c1012dfe21.shtml
https://economy-finance.ec.europa.eu/document/download/f5827354-8501-49cb-bf2d-13f2f7a9444f_en?filename=dp199_en.pdf
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