Domestic dogs (Canis familiaris) use a physical marker to locate hidden food
Animal Cognition (2006) - Comment
pubmed: 15846526  doi: 10.1007/s10071-005-0256-0  issn: 1435-9448  issn: 1435-9456 

Julia Riedel, David Buttelmann, Josep Call, Michael Tomasello