David Carmel Eitan Farchi Yael Petruschka Aya Soffer Automatic query refinement using lexical affinities with maximal information gain. 283-290 2002 conf/sigir/2002 SIGIR http://doi.acm.org/10.1145/564376.564427 db/conf/sigir/sigir2002.html#CarmelFPS02