APA (7th ed.) Citation

Melis, A. P., Engelmann, J. M., & Warneken, F. (2018). Correspondence: Chimpanzee helping is real, not a byproduct. Nature Portfolio.

Chicago Style (17th ed.) Citation

Melis, Alicia P., Jan M. Engelmann, and Felix Warneken. Correspondence: Chimpanzee Helping Is Real, Not a Byproduct. Nature Portfolio, 2018.

MLA (8th ed.) Citation

Melis, Alicia P., et al. Correspondence: Chimpanzee Helping Is Real, Not a Byproduct. Nature Portfolio, 2018.