@article{MAN_1966__163_161355,
     author = {V. PTAK},
     title = {Some {Metric} {Aspects} of the {Open} {Mapping} and {Closed} {Graph} {Theorems.}},
     journal = {Mathematische Annalen},
     pages = {95--104},
     publisher = {mathdoc},
     volume = {163},
     year = {1966},
     zbl = {0138.37602},
     url = {http://geodesic.mathdoc.fr/item/MAN_1966__163_161355/}
}