@article{MZ_1988__199_1_173975,
     author = {Carl L. DeVito},
     title = {On {Pt\'ak's} {Generalization} of the {Open-Mapping} and {Closed-Graph} {Theorems.}},
     journal = {Mathematische Zeitschrift},
     pages = {399--406},
     publisher = {mathdoc},
     volume = {199},
     number = {1},
     year = {1988},
     zbl = {0643.46004},
     url = {http://geodesic.mathdoc.fr/item/MZ_1988__199_1_173975/}
}