@article{AFM_1963_316-335_a10,
     author = {F. W. Gehring and Gunnar af H\"allstr\"om},
     title = {A distrotion theorem for functions univalent in an annulus},
     journal = {Annales Fennici Mathematici},
     publisher = {mathdoc},
     volume = {316-335},
     year = {1963},
     doi = {10.5186/aasfm.1963.325},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.5186/aasfm.1963.325/}
}