Smirnov, O., Dawes, C. T., Fowler, J. H., Johnson, T., & McElreath, R. (2010). The behavioral logic of collective action: Partisans cooperate and punish more than nonpartisans. Political Psychology, 31(4), 595-616. doi:10.1111/j.1467-9221.2010.00768.x.