JONEK-KOWALSKA, Izabela; TUREK, Marian. Possibilities of Improving the Efficiency of Mining Companies. Equilibrium. Equilibrium. Quarterly Journal of Economics and Economic Policy, [S. l.], v. 6, n. 2, p. 91–108, 2011. DOI: 10.12775/EQUIL2011.014. Disponível em: https://apcz.umk.pl/EQUIL/article/view/EQUIL2011.014. Acesso em: 8 jul. 2025.