Zhang Le's Max ent page:
http://homepages.inf.ed.ac.uk/s0450736/maxent.html

Ratnaparki page:
http://www.informatik.uni-trier.de/~ley/db/indices/a-tree/r/Ratnaparkhi:Adwait.html


Berger's tutorial
http://www.cs.cmu.edu/afs/cs/user/aberger/www/html/tutorial/tutorial.html