@article{CMH_1965__40_139298,
     author = {J. Clunie and W.K. Hayman},
     title = {The spherical derivative of integral and meromorphic functions.},
     journal = {Commentarii mathematici Helvetici},
     pages = {117--148},
     publisher = {mathdoc},
     volume = {40},
     year = {1965},
     zbl = {0142.04303},
     url = {http://geodesic.mathdoc.fr/item/CMH_1965__40_139298/}
}