TY  - JOUR
AU  - Yu. P. Krivenkov
TI  - Sufficient optimality conditions for problems with second order differential equations of elliptic type in the presence of phase constraints
JO  - Differencialʹnye uravneniâ
PY  - 1975
SP  - 85
EP  - 99
VL  - 11
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1975_11_1_a10/
LA  - ru
ID  - DE_1975_11_1_a10
ER  -