de Dreu, C. K. W., Greer, L. L.
, van Kleef, G. A., Shalvi, S., & Handgraaf, M. J. J. (2011).
Oxytocin promotes human ethnocentrism.
Proceedings of the National Academy of Sciences of the United States of America,
108(4), 1262-1266.
https://doi.org/10.1073/pnas.1015316108