Burton-Chellew, M., Ross-Gillespie, A., West, S., & Society, H. B. a. E. (2010). Cooperation in humans: Competition between groups and proximate emotions. Elsevier.

Burton-Chellew, M., A. Ross-Gillespie, S. West, and Human Behavior and Evolution Society. Cooperation in Humans: Competition Between Groups and Proximate Emotions. Elsevier, 2010.

Burton-Chellew, M., et al. Cooperation in Humans: Competition Between Groups and Proximate Emotions. Elsevier, 2010.