FRANCISZKOWSKA, Sara; WĘGRZYN, Anna. The phenomenon of gray economy in Poland – causes, effects andreduction methods. Journal of Finance and Financial Law, [S. l.], v. 4, n. 24, p. 33–48, 2019. DOI: 10.18778/2391-6478.4.24.03. Disponível em: https://czasopisma.uni.lodz.pl/fipf/article/view/7258. Acesso em: 8 dec. 2025.