Wartena, C. & Wibbels, M. (2011), Improving Tag-Based Recommendation by Topic Diversification, in Paul Clough; Colum Foley; Cathal Gurrin; Gareth Jones; Wessel Kraaij; Hyowon Lee & Vanessa Mudoch, ed., 'Advances in Information Retrieval' , Springer, Berlin/Heidelberg , pp. 43--54 .