TY  - JOUR
AU  - V. E. Kashkakha
TI  - On the zeros of the gradient of the solutions of second-order homogeneous elliptic equations in the plane
JO  - Doklady Akademii Nauk
PY  - 1971
SP  - 523
EP  - 525
VL  - 199
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1971_199_3_a3/
LA  - ru
ID  - DAN_1971_199_3_a3
ER  -