APA (7th ed.) Citation

Dunbar, R., & Botha, R. (2009). Why only humans have language. Oxford University Press.

Chicago Style (17th ed.) Citation

Dunbar, R., and R. Botha. Why Only Humans Have Language. Oxford University Press, 2009.

MLA (9th ed.) Citation

Dunbar, R., and R. Botha. Why Only Humans Have Language. Oxford University Press, 2009.

Warning: These citations may not always be 100% accurate.