TY  - JOUR
AU  - E. S. Birger
AU  - G. A. Kalyabin
TI  - Theory of Weyl circles in the case of a nonselfadjoint system of second order differential equations
JO  - Differencialʹnye uravneniâ
PY  - 1976
SP  - 1531
EP  - 1540
VL  - 12
IS  - 9
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1976_12_9_a0/
LA  - ru
ID  - DE_1976_12_9_a0
ER  -