@article{CMUC_1967_8_3_a4,
     author = {Zizler, V\'aclav E.},
     title = {On the differentiability of mappings in {Banach} spaces},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {415--430},
     year = {1967},
     volume = {8},
     number = {3},
     mrnumber = {0227772},
     zbl = {0179.19101},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1967_8_3_a4/}
}