1. D. Aurangzeb and K. Asif, “Factors Effecting Unemployment: A Cross Country Analysis,” in International Journal of Academic Research in Business and Social Sciences, 2013, 3, pp. 219–230.
2. L. Ball and J. T. Jalles and P. Loungani, “Do forecasters believe in Okun’s law? An assessment of unemployment and output forecasts”, International monetary center working paper 2014, 24.
3. M. Clar-Lopez, and J. López-Tamayo and R. Ramos, “Unemployment forecasts, time varying coefficient models and the Okun’s law in Spanish regions,” Economics and Bussiness letters, 2013, 3.
4. Eurostat: Unemployment statistics, Eurostat web page (ec.europa.eu), update 03/2016. http://ec.europa.eu/eurostat/statistics-explained/index.php/Unemployment_statistics
5. R. Kosfeld and Ch. Dreger, “Thresholds for employment and unemployment. A spatial analysis of German Regional Labour Markets 1992–2000,” in ERSA conference papers ersa05p39, European Regional Science Association, 2006.