Kees van Deemter Brigitte Krenn Paul Piwek Martin Klesen Marc Schröder Stefan Baumann 1219-1244 2008 172 Artif. Intell. 10 http://dx.doi.org/10.1016/j.artint.2008.02.002 db/journals/ai/ai172.html#DeemterKPKSB08