The influence of local enhancement on choice performances in African Grey parrots (Psittacus erithacus) and jackdaws (Corvus monedula)
Journal of Comparative Psychology (2012) - Comment
pubmed: 22866773  doi: 10.1037/a0028209  issn: 1939-2087  issn: 0735-7036 

Sandra Mikolasch, Kurt Kotrschal, Christian Schloegl