Baozhen Wu Tingting He Yong Zhang Li Li Long Chen Research on Popular Words and Phrases Extraction of Network Base on PAT TREE. 723-726 2008 CSSE (1) http://dx.doi.org/10.1109/CSSE.2008.1210 conf/csse/2008-1 db/conf/csse/csse2008-1.html#WuHZLC08