Ryosuke Saga Masahiro Terachi Zhongqi Sheng Hiroshi Tsuji FACT-Graph: Trend Visualization by Frequency and Co-occurrence. 308-315 2008 KI http://dx.doi.org/10.1007/978-3-540-85845-4_38 conf/ki/2008 db/conf/ki/ki2008.html#SagaTST08