1. What does a basis of F(a, b) look like?;Cohen;Math. Ann.,1981
2. Word Processing in Groups;Epstein,1992
3. Incompressible surfaces in punctured-torus bundles;Floyd;Topology Appl.,1982
4. Small cancellation theory and automatic groups;Gersten;Invent. Math.,1990
5. W.P. Thurston, The geometry and topology of 3-manifolds, Preprint, Princeton University, Princeton, NJ.