Joachim Giesen Dieter Mitsche Eva Schuberth Collaborative Ranking: An Aggregation Algorithm for Individuals' Preference Estimation. 58-67 2007 conf/aaim/2007 AAIM http://dx.doi.org/10.1007/978-3-540-72870-2_6 db/conf/aaim/aaim2007.html#GiesenMS07