@article{10_21136_MB_1999_125974,
     author = {Graef, John R. and Yang, Bo and Zhang, B. G.},
     title = {Existence of nonoscillatory and oscillatory solutions of neutral differential equations with positive and negative coefficients},
     journal = {Mathematica Bohemica},
     pages = {87--102},
     publisher = {mathdoc},
     volume = {124},
     number = {1},
     year = {1999},
     doi = {10.21136/MB.1999.125974},
     mrnumber = {1687484},
     zbl = {0937.34066},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/MB.1999.125974/}
}