@article{10_21136_CMJ_1974_101265,
     author = {Pt\'ak, Vlastimil},
     title = {A quantitative refinement of the closed graph theorem},
     journal = {Czechoslovak Mathematical Journal},
     pages = {503--506},
     publisher = {mathdoc},
     volume = {24},
     number = {3},
     year = {1974},
     doi = {10.21136/CMJ.1974.101265},
     mrnumber = {0348431},
     zbl = {0315.46007},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1974.101265/}
}