TY  - JOUR
AU  - V. I. Borzdyko
TI  - A topological method for proving the existence of positive periodic solutions for functional-differential equations
JO  - Differencialʹnye uravneniâ
PY  - 1990
SP  - 1671
EP  - 1678
VL  - 26
IS  - 10
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1990_26_10_a1/
LA  - ru
ID  - DE_1990_26_10_a1
ER  -