Avare Stewart Ernesto Diaz-Aviles Wolfgang Nejdl Leandro Balby Marinho Alexandros Nanopoulos Lars Schmidt-Thieme Cross-tagging for personalized open social networking. 271-278 2009 Hypertext http://doi.acm.org/10.1145/1557914.1557960 conf/ht/2009 db/conf/ht/ht2009.html#StewartDNMNS09