Tetsutaro Watanabe Takashi Kobayashi Haruo Yokota A Method for Searching Keyword-Lacking Files Based on Interfile Relationships. 14-15 2008 OTM Workshops http://dx.doi.org/10.1007/978-3-540-88875-8_7 conf/otm/2008-w db/conf/otm/otm2008-w.html#WatanabeKY08