https://pub.norden.org/nord2020-001/#
http://www.votewatch.eu/blog/alliances-matter-political-networks-the-rule-of-law-principles-and-the-split-of-eu-money-mff/
https://onlinelibrary.wiley.com/doi/epdf/10.1111/jcms.13411
https://www.eca.europa.eu/Lists/ECADocuments/SR21_08/SR_Frontex_EN.pdf