@article{MAN_1971__195_162225,
     author = {Akio Hattori},
     title = {Genera of {Ramified} {Coverings.}},
     journal = {Mathematische Annalen},
     pages = {208--226},
     publisher = {mathdoc},
     volume = {195},
     year = {1971},
     zbl = {0226.57017},
     url = {http://geodesic.mathdoc.fr/item/MAN_1971__195_162225/}
}