Ramesh Nallapati Amr Ahmed William W. Cohen Eric P. Xing Sparse Word Graphs: A Scalable Algorithm for Capturing Word Correlations in Topic Models. 343-348 2007 ICDM Workshops http://doi.ieeecomputersociety.org/10.1109/ICDMW.2007.100 conf/icdm/2007w db/conf/icdm/icdmw2007.html#NallapatiACX07