@article{JRAM_1991__417_153331,
     author = {Rita Pardini},
     title = {Canonical images of surfaces.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {215--219},
     year = {1991},
     volume = {417},
     zbl = {0721.14020},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1991__417_153331/}
}