On the existence of Jenkins-Strebel differentials using harmonic maps from surfaces to graphs. Wolf, Michael — 1995 Annales Academiae Scientiarum Fennicae. Series A I. Mathematica
Teichmüller space is not Gromov hyperbolic. Masur, Howard A.; Wolf, Michael — 1995 Annales Academiae Scientiarum Fennicae. Series A I. Mathematica