van Schaik, C P; Burkart, J M; Damerius, Laura; Forss, Sofia; Koops, Kathelijne; van Noordwijk, M A; Schuppli, Caroline (2016). The reluctant innovator: orangutans and the phylogeny of creativity. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 371(1690):20150183.
Willems, E P; Arseneau, T Jean M; Schleuning, Xenia; van Schaik, C P (2015). Communal range defence in primates as a public goods dilemma. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 370(1683):20150003.