@article{PM_1991_1991_1_a19,
     author = {Forte Cunto, Ana},
     title = {Continuidad de la funci\'on de visibilidad.},
     journal = {Publicacions matem\`atiques},
     pages = {323-332},
     publisher = {mathdoc},
     volume = {35},
     number = {2},
     year = {1991},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PM_1991_1991_1_a19/}
}