Social conditioned place preference in the captive ground squirrel (Ictidomys tridecemlineatus): Social reward as a natural phenotype
Journal of Comparative Psychology (2015) - Comment
pubmed: 26147706  doi: 10.1037/a0039435  issn: 1939-2087  issn: 0735-7036 

Garet P. Lahvis, Jules B. Panksepp, Bruce C. Kennedy, Clarinda R. Wilson, Dana K. Merriman