Willi Richert Bernd Kleinjohann Lisa Kleinjohann Trading off Impact and Mutation of Knowledge by Cooperatively Learning Robots. 189-198 2006 BICC http://dx.doi.org/10.1007/978-0-387-34733-2_19 conf/ifip10/2006 db/conf/ifip10/bicc2006.html#RichertKK06