https://taxfoundation.org/flat-tax-state-income-tax-reform/
http://www.imf.org/en/News/Articles/2017/05/15/mcs05152017-Germany-Staff-Concluding-Statement-of-the-2017-Article-IV-Mission
https://www.niesr.ac.uk/sites/default/files/UK%20Economy%20Press%20Release%20-NIER%20No245%20%20August%202018%20-%20EMBARGOED%20until%2000.01%20Wednesday%201st%20August.pdf
https://www.linkiesta.it/2020/05/coronavirus-recessione-italia-commissione-gentiloni/