Visalberghi, E., Sirianni, G., Fragaszy, D., & Boesch, C. (2015). Percussive tool use by Taï Western chimpanzees and Fazenda Boa Vista bearded capuchin monkeys: A comparison. Philosophical Transactions of the Royal Society of London, Series B: Biological Sciences, 370(1682): 20140351. doi:10.1098/rstb.2014.0351.