Dominik Lücke Till Mossakowski Diedrich Wolter Qualitative Reasoning about Convex Relations. 426-440 2008 Spatial Cognition http://dx.doi.org/10.1007/978-3-540-87601-4_30 conf/spatialCognition/2008 db/conf/spatialCognition/spatialCognition2008.html#LuckeMW08