Jaak Henno Yasushi Kiyoki Takehiro Tokuda Hannu Jaakkola Naofumi Yoshida Information Modelling and Knowledge Bases XXIII, 21st European-Japanese Conference on Information Modelling and Knowledge Bases (EJC 2011), Tallinn, Estonia, June, 6-10, 2011 2012 IOS Press Frontiers in Artificial Intelligence and Applications 237 978-1-60750-991-2 http://www.booksonline.iospress.nl/Content/View.aspx?piid=29363 EJC db/conf/ejc/ejc2011.html