Pika, Simone Department of Developmental and Comparative Psychology, Max Planck Institute for Evolutionary Anthropology, Max Planck Society;
Pika, S. (2003). The gestural communication of subadult gorillas (Gorilla Gorilla) and subadult bonobos (Pan Paniscus) in captivity. PhD Thesis, Westfälische Wilhelms-Universität Münster, Münster.