TY  - JOUR
AU  - B. T. Polyak
TI  - Semicontinuity of integral functionals and existence theorems on extremal problems
JO  - Sbornik. Mathematics
PY  - 1969
SP  - 59
EP  - 77
VL  - 7
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/SM_1969_7_1_a2/
LA  - en
ID  - SM_1969_7_1_a2
ER  -