@article{EJDE_2000__2000__a127,
     author = {Elabbasy,  El M. and Hegazi,  A.S. and Saker,  S.H.},
     title = {Oscillation of solutions to delay differential equations with positiv and negative coefficients},
     journal = {Electronic journal of differential equations},
     year = {2000},
     volume = {2000},
     zbl = {0944.34056},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2000__2000__a127/}
}