In this post for Social Europe, Branko Milanovic discussed the inequality successive EU enlargements have enhanced.
B. Milanovic. Cambridge, MA: Belknap Press. 2016.
M. Corak, A. Beck, and M. Tienda. The ANNALS of the American Academy of Political and Social Science. no. 643, no. 1. pp. 134–159. 2012.
B. Milanovic. Global Policy. vol. 3, no. 2. pp. 125-134. 2012.