Umiński, Paweł. “Potential Introduction of Flat Tax on Personal Income in the United States of America in 2007 and a Distribution of Revenue”. Equilibrium. Equilibrium. Quarterly Journal of Economics and Economic Policy 5, no. 2 (December 1, 2010): 221–231. Accessed July 23, 2024. https://apcz.umk.pl/EQUIL/article/view/EQUIL.2010.037.