@article{10_21136_CMJ_1959_100379,
     author = {Pt\'ak, Vlastimil},
     title = {On the closed graph theorem},
     journal = {Czechoslovak Mathematical Journal},
     pages = {523--527},
     year = {1959},
     volume = {9},
     number = {4},
     doi = {10.21136/CMJ.1959.100379},
     mrnumber = {0115061},
     zbl = {0093.12002},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1959.100379/}
}