Borlea, S. N., M. V. Achim, and M. G. Miron. “Corruption, Shadow Economy and Economic Growth: An Empirical Survey Across the European Union Countries”. Studia Universitatis Vasile Goldiș Arad, Seria Științe Economice, Vol. 27, no. 2, June 2017, pp. 19-32, https://publicatii.uvvg.ro/index.php/studiaeconomia/article/view/191.