@article{MAN_1975__218_162790,
     author = {Alan Durfee and Louis Kauffman},
     title = {Periodicity of {Branched} {Cyclic} {Covers.}},
     journal = {Mathematische Annalen},
     pages = {157--174},
     year = {1975},
     volume = {218},
     zbl = {0296.55001},
     url = {http://geodesic.mathdoc.fr/item/MAN_1975__218_162790/}
}