http://research.microsoft.com/users/marycz/ht98.htm

http://javelina.cet.middlebury.edu/lsa/out/lsa_definition.htm

http://www-psych.nmsu.edu/~pfoltz/cois/filtering-cois.html

http://lsi.research.telcordia.com/lsi/papers/execsum.html

http://www.cs.berkeley.edu/~jasonh/classes/sims240/sims-240-final-paper-lsi.htm

http://www.cs.utk.edu/~berry/lsi++/node8.html