Yasufumi Kaneko Satoshi Nakamura Hiroaki Ohshima Katsumi Tanaka Query Relaxation Based on Users' Unconfidences on Query Terms and Web Knowledge Extraction. 71-81 2008 ICADL http://dx.doi.org/10.1007/978-3-540-89533-6_8 conf/icadl/2008 db/conf/icadl/icadl2008.html#KanekoNOT08