Are they in or are they out: Questioning category relations in the study of helping

Ryan, C., Reicher, S., & Alexander Haslam, S. (2017). Are they in or are they out: Questioning category relations in the study of helping. In Intergroup Helping (pp. 249–267). Springer International Publishing. https://doi.org/10.1007/978-3-319-53026-0_12