Stefaniak-Kopoboru, Joanna, and Joanna Kuczewska. “Export Specialization in Services of the Visegrad Countries”. Equilibrium. Quarterly Journal of Economics and Economic Policy 11, no. 2 (June 30, 2016): 265–284. Accessed January 29, 2023. http://economic-research.pl/Journals/index.php/eq/article/view/136.