@article{PORMA_2001__58_2_49137,
     author = {Ferreira, Jos\'e M.},
     title = {Oscillations and nonoscillations in retarded equations.},
     journal = {Portugaliae mathematica},
     pages = {127--138},
     publisher = {mathdoc},
     volume = {58},
     number = {2},
     year = {2001},
     zbl = {0983.45001},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_2001__58_2_49137/}
}