The Goulden-Jackson Cluster Method: Extensions, Applications and   Implementations
  The powerful (and so far under-utilized) Goulden-Jackson Cluster method for finding the generating function for the number of words avoiding, as factors, the members of a prescribed set of `dirty words', is tutorialized and extended in various directions. The authors' Maple implementations, contained in several Maple packages available from this paper's website (http://www.math.temple.edu/~zeilberg/gj.html), are described and explained. 
John Noonan (Mt. Vernon Nazarene College), Doron Zeilberger (Temple   University)