Böhm, R., Rockenbach, B., & Zimmermann, J. (2018).
"United We Stand, Divided We Fall: The Limitations of Between-Group Comparisons for Fostering Within-Group Cooperation." Journal of Economic Psychology, 69, 19–29.
Zimmermann, J., & Efferson, C. (2017).
"One-Shot Reciprocity Under Error Management Is Unbiased and Fragile." Evolution and Human Behavior, 38(1), 39–47.