PIĄTKOWSKI, Paweł. Public Debt as a Problem of the European Union. Oeconomia Copernicana, [S. l.], v. 5, n. 2, p. 21–34, 2014. DOI: 10.12775/OeC.2014.011. Disponível em: https://apcz.umk.pl/OeC/article/view/OeC.2014.011. Acesso em: 19 mar. 2025.