https://scholar.harvard.edu/files/rogoff/files/nber26760_why_is_euro_punching_below_its_weight.pdf
https://energy.ec.europa.eu/system/files/2022-05/COM_2022_230_1_EN_ACT_part1_v5.pdf
https://www.nao.org.uk/wp-content/uploads/2018/01/PFI-and-PF2.pdf
https://www.bancaditalia.it/media/approfondimenti/2019/pop-bari/approfondimenti-popBari.pdf