Podstawka, M., & Suchodolski, B. (2019). Measurement and Assessment of the Level of Economic Development of the Counties of the Opolskie Voivodeship. Zeszyty Naukowe UPH Seria Administracja I Zarządzanie, 47(120), 25–32. https://doi.org/10.34739/zn.2019.47.03