TY  - JOUR
AU  - V. I. Plotnikov
TI  - On the differentiability of the solutions of variation problems in a non-parametric form
JO  - Doklady Akademii Nauk
PY  - 1957
SP  - 746
EP  - 749
VL  - 116
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1957_116_5_a7/
LA  - ru
ID  - DAN_1957_116_5_a7
ER  -