MICHALAK, Aneta. Specific risk in hard coal mining industry in Poland. Forum Scientiae Oeconomia, [S. l.], v. 5, n. 1, p. 71–77, 2017. DOI: 10.23762/fso_vol5no1_6. Disponível em: https://ojs.wsb.edu.pl/index.php/fso/article/view/281. Acesso em: 18 sep. 2026.