Sanjiv K. Bhatia Jitender S. Deogun Vijay V. Raghavan User Profiles for Information Retrieval. 102-111 1991 conf/ismis/1991 ISMIS db/conf/ismis/ismis91.html#BhatiaDR91 http://dx.doi.org/10.1007/3-540-54563-8_74