Ramnath Balasubramanyan William W. Cohen Block-LDA: Jointly modeling entity-annotated text and entity-entity links. 450-461 2011 SDM http://siam.omnibooksonline.com/2011datamining/data/papers/058.pdf#page=1 conf/sdm/2011 db/conf/sdm/sdm2011.html#BalasubramanyanC11