Goerg, Sebastian Max Planck Institute for Research on Collective Goods, Max Planck Society;
http://www.sciencedirect.com/science/article/pii/S0014292116300708 (Any fulltext)
Chmura, T., Goerg, S., & Weiss, P. (2016). Natural groups and economic characteristics as driving forces of wage discrimination. European Economic Review, 90, 178-200.