The use of the bared-teeth display during play fighting in Tonkean macaques (Macaca tonkeana): sometimes it is all about oneself
Journal of Comparative Psychology (2011) - Comment
pubmed: 21823787  doi: 10.1037/a0024514  issn: 1939-2087  issn: 0735-7036 

Sergio M. Pellis, Vivien C. Pellis, Christine J. Reinhart, Bernard Thierry