1. D. Aharonov and U. Srebro,Boundary behavior of conformal and quasiconformal mappings, Ann. Acad. Sci. Fenn. AI8 (1982), 139–148.
2. M. Essen,Boundary behavior of univalent functions satisfying a Hölder condition, Proc. Am. Math. Soc.83 (1981), 83–84.
3. F. W. Gehring,Symmetrization of rings in space, Trans. Am. Math. Soc.101 (1961), 499–519.
4. F. W. Gehring,The Carathéodory convergence theorem for quasiconformal mappings in space, Ann. Acad. Sci. Fenn. AI336/11 (1963), 1–21.
5. F. W. Gehring and O. Martio,Lipschitz classes and quasiconformal mappings, Ann. Acad. Sci. Fenn. AI10 (1985), 203–219.