TY  - JOUR
AU  - M. Sh. Birman
TI  - The discrete spectrum in the gaps of a second-order perturbed periodic operator
JO  - Funkcionalʹnyj analiz i ego priloženiâ
PY  - 1991
SP  - 89
EP  - 92
VL  - 25
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/FAA_1991_25_2_a18/
LA  - ru
ID  - FAA_1991_25_2_a18
ER  -