Ewa Orlowska Ingrid Rewitzky Discrete Duality and Its Applications to Reasoning with Incomplete Information. 51-56 2007 conf/rseisp/2007 RSEISP http://dx.doi.org/10.1007/978-3-540-73451-2_7 db/conf/rseisp/rseisp2007.html#OrlowskaR07