@article{10_2307_2661392,
     author = {M. Bonk and A. Eremenko},
     title = {Covering properties of meromorphic functions, negative curvature and spherical geometry},
     journal = {Annals of mathematics},
     year = {2000},
     volume = {152},
     number = {2},
     doi = {10.2307/2661392},
     zbl = {0970.30016},
     url = {http://geodesic.mathdoc.fr/articles/10.2307/2661392/}
}