Patrick Bosc Olivier Pivert Olivier Soufflet Anti-division Queries with Ordinal Layered Preferences. 769-780 2009 ECSQARU http://dx.doi.org/10.1007/978-3-642-02906-6_66 conf/ecsqaru/2009 db/conf/ecsqaru/ecsqaru2009.html#BoscPS09