@article{CMUC_1981__22_3_a8,
     author = {Zaj{\'\i}\v{c}ek, Lud\v{e}k},
     title = {On approximate {Dini} derivates and one-sided approximate derivatives of arbitrary functions},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {549--560},
     publisher = {mathdoc},
     volume = {22},
     number = {3},
     year = {1981},
     mrnumber = {633582},
     zbl = {0487.26004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1981__22_3_a8/}
}