1. Carstensen K., Toubal F., Foreign Direct Investment in Central and Eastern European Countries: A Dynamic Panel Analysis, „Journal of Comparative Economics”, vol. 32, 2004, issue 1, no. 1143.
2. Central Intelligence Agency, „The World Factbook”, https://www.cia.gov/the-world-factbook/.
3. Fordymacki P., Strategie rozwoju państw Europy Środkowo-Wschodniej, https://journals.indexcopernicus.com/api/file/viewByFileId/691480.pdf.
4. IMD, https://www.imd.org/wcc/world-competitiveness-reflections/the-global-competitiveness-report/.
5. Institute of Labor Economics, https://www.iza.org/publications/dp/6946/the-economic-security-index-a-new-measure-for-research-and-policy--analysis.