Anton Schwaighofer Joaquin Quiñonero Candela Thomas Borchert Thore Graepel Ralf Herbrich Scalable clustering and keyword suggestion for online advertisements. 27-36 2009 KDD Workshop on Data Mining and Audience Intelligence for Advertising http://doi.acm.org/10.1145/1592748.1592753 conf/kdd/2009adkdd db/conf/kdd/adkdd2009.html#SchwaighoferCBGH09