TY  - JOUR
AU  - Preiss, David
TI  - On the first derivative of real functions (Preliminary communication)
JO  - Commentationes Mathematicae Universitatis Carolinae
PY  - 1970
SP  - 817
EP  - 822
VL  - 11
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/CMUC_1970__11_4_a12/
LA  - en
ID  - CMUC_1970__11_4_a12
ER  -