TY  - JOUR
AU  - Durdil, Jiří
TI  - On the geometric characterization of differentiability. I.
JO  - Commentationes Mathematicae Universitatis Carolinae
PY  - 1974
SP  - 521
EP  - 540
VL  - 15
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/CMUC_1974__15_3_a10/
LA  - en
ID  - CMUC_1974__15_3_a10
ER  -