I'm seeking a reference or a sketch for any sort of normal form that would enable rapid enumeration without redundancies of the elements of hyperbolic triangle groups and/or von Dyck groups. 



Normal form(s) for the elements of hyperbolic triangle groups
[This](http://www.math.rwth-aachen.de/~Gerhard.Hiss/Students/DiplomarbeitPfeiffer.pdf) thesis contains a complete rewriting system for every triangle group (see Section C at the end of the thesis). Then normal forms are just words that do not contain left parts of the rewriting rules (which is just a finite set of words). This gives enumeration of all elements without redundancies. 


