https://ecipe.org/wp-content/uploads/2020/08/ECI_20_PolicyBrief_06_2020_LY06.pdf
https://www.europarl.europa.eu/doceo/document/B-9-2020-0098_EN.html?utm_source=POLITICO.EU&utm_campaign=3e49ba2509-EMAIL_CAMPAIGN_2020_02_13_05_53&utm_medium=email&utm_term=0_10959edeb5-3e49ba2509-190380769
http://www.cesifo-group.de/ifoHome/publications/working-papers/CESifoWP/CESifoWPdetails?wp_num=6430&CESifoWP.search=+