End state copying by humans (Homo sapiens): implications for a comparative perspective on cumulative culture
Journal of Comparative Psychology (2012) - Comment
pubmed: 22468937  doi: 10.1037/a0026828  issn: 1939-2087  issn: 0735-7036 

Christine A. Caldwell, Kerstin Schillinger, Cara L. Evans, Lydia M. Hopper