Blaz Fortuna Eduarda Mendes Rodrigues Natasa Milic-Frayling Improving the classification of newsgroup messages through social network analysis. 877-880 2007 conf/cikm/2007 CIKM http://doi.acm.org/10.1145/1321440.1321565 db/conf/cikm/cikm2007.html#FortunaRM07