Seiji Egawa Yoshihide Kato Shigeki Matsubara Sentence compression by structural conversion of parse tree. 544-550 2008 ICDIM http://dx.doi.org/10.1109/ICDIM.2008.4746757 conf/icdim/2008 db/conf/icdim/icdim2008.html#EgawaKM08