1. Conformal Invariants: Topics in Geometric Function Theory;Ahlfors,1973
2. An extremal problem for quasiconformal mappings and a theorem of Thurston;Bers;Acta Mathematica,1978
3. Quasiconformal mappings and Teichmuller's theorem;Bers,1960
4. On the density of Strebel differentials;Douady;Inventiones Math.,1975