TY  - JOUR
AU  - A. G. Ramm
TI  - The existence of periodic solutions for certain nonlinear problems
JO  - Differencialʹnye uravneniâ
PY  - 1977
SP  - 1701
EP  - 1708
VL  - 13
IS  - 9
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1977_13_9_a15/
LA  - ru
ID  - DE_1977_13_9_a15
ER  -