TY  - JOUR
AU  - V. S. Balaganskii
TI  - Necessary Conditions for Differentiability of Distance Functions
JO  - Matematičeskie zametki
PY  - 2002
SP  - 815
EP  - 820
VL  - 72
IS  - 6
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MZM_2002_72_6_a2/
LA  - ru
ID  - MZM_2002_72_6_a2
ER  -