David Newman Kat Hagedorn Chaitanya Chemudugunta Padhraic Smyth Subject metadata enrichment using statistical topic models. 366-375 2007 conf/jcdl/2007 JCDL http://doi.acm.org/10.1145/1255175.1255248 db/conf/jcdl/jcdl2007.html#NewmanHCS07