@article{AFM_1989_14_2_a14,
     author = {F.W. Gehring and Ch. Pommerenke},
     title = {Circular distortion of curves and quasicircles},
     journal = {Annales Fennici Mathematici},
     pages = {381--390},
     publisher = {mathdoc},
     volume = {14},
     number = {2},
     year = {1989},
     doi = {10.5186/aasfm.1989.1406},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.5186/aasfm.1989.1406/}
}