TY  - JOUR
AU  - O. I. Nikonov
TI  - Some extremal properties of observable differential systems
JO  - Differencialʹnye uravneniâ
PY  - 1985
SP  - 236
EP  - 240
VL  - 21
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1985_21_2_a5/
LA  - ru
ID  - DE_1985_21_2_a5
ER  -