[1]   Christopher M. Bishop, “Pattern Recognition and Machine Learning”, Springer 2006.

[2]   Li, YH and Jain, AK, “Classification of text documents”. The Computer Journal: 1998, 41(8):537-546.

[3]   Jason Rennie, “Home Page for 20 Newsgroups Data Set”. MIT CSAIL, http://people.csail.mit.edu/jrennie/20Newsgroups/. April 20, 2009.