@article{CMUC_1967_8_3_a12,
     author = {Durdil, Ji\v{r}{\'\i}},
     title = {On the differentiability of {Urysohn} and {Nemyckii} operators},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {515--553},
     year = {1967},
     volume = {8},
     number = {3},
     mrnumber = {0227822},
     zbl = {0165.48904},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1967_8_3_a12/}
}