Call, Josep Department of Developmental and Comparative Psychology, Max Planck Institute for Evolutionary Anthropology, Max Planck Society;
Helme, A. E., Call, J., Clayton, N. S., & Emery, N. J. (2006). What do bonobos (Pan paniscus) understand about physical contact? Journal of Comparative Psychology, 120(3), 294-302. doi:10.1037/0735-7036.120.3.294.