Matkowski, Z., Prochniak, M. Real Economic Convergence in the EU Accession Countries. International Journal of Applied Econometrics and Quantitative Studies (Euro-American Association of Economic Development): 5–38. [2020-06-10]. (原始内容存档于2020-06-10).
Matkowski, Z., Prochniak, M. Real Economic Convergence in the EU Accession Countries. International Journal of Applied Econometrics and Quantitative Studies (Euro-American Association of Economic Development): 5–38. [2020-06-10]. (原始内容存档于2020-06-10).