Does anyone knows a good book or script about Dehn Twists in the sense of graphs. More precisely: I need to know how a Dehn Twist yields an automorphism of a group or subgroups. I want to know something about the realtionship between dehn twists and graph of groups.
I know that my request is not nice formulated, but i didn't found any good introduction about this theme in the internet yet. I always get defintions for dehn twists in the sense of surfaces. But i don't know, how to conclude or educe something about groups in the sense of geometric group theory.
Thanks for help.