1. Antonacci, D., Norscia, I., & Palagi, E. (2010). Stranger to familiar: Wild strepsirhines manage xenophobia by playing. PLoS One, 5(10), e13218.
https://doi.org/10.1371/journal.pone.0013218
.
2. Bernstein, I. S., & Gordon, T. P. (1974). The function of aggression in primate societies: Uncontrolled aggression may threaten human survival, but aggression may be vital to the establishment and regulation of primate societies and sociality. American Scientist, 62(3), 304–311. Retrieved from
www.jstor.org/stable/27844884
.
3. Fisher, J. (1954). Evolution and bird sociality. In J. Huxley, A. C. Hardy, & E. B. Ford (Eds.), Evolution as a process (pp. 71–83). London: George Allen & Unwin Ltd..
4. Fragaszy, D., Baer, J., & Adams-Curtis, L. (1994). Introduction and integration of strangers into captive groups of tufted capuchins (Cebus apella). International Journal of Primatology, 15(3), 399–420.
https://doi.org/10.1007/BF02696101
.
5. Goodall, J. (1986). The chimpanzees of Gombe: Patterns of behavior. Cambridge, MA: The Belknap Press of Harvard University Press.