MATYJAS, Zbigniew. The impact of industry-level effects on the financial performance of Polish public companies. Acta Universitatis Nicolai Copernici Ekonomia. Online. 5 July 2011. Vol. 42, no. 1, pp. 95-104. [Accessed 8 July 2025]. DOI 10.12775/AUNC_ECON.2011.007.