TY  - JOUR
AU  - Ferreira, José M.
TI  - Nonnegative point spectrum for differential equations with infinite delays
JO  - Portugaliae mathematica
PY  - 1981
SP  - 239
EP  - 251
VL  - 40
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/PORMA_1981__40_2_115447/
LA  - en
ID  - PORMA_1981__40_2_115447
ER  -