Claudette Cayrol Sylvie Doutre Jérôme Mengin On Decision Problems Related to the Preferred Semantics for Argumentation Frameworks. 377-403 2003 13 J. Log. Comput. 3 http://www3.oup.co.uk/logcom/hdb/Volume_13/Issue_03/130377.sgm.abs.html db/journals/logcom/logcom13.html#CayrolDM03