@article{MASLO_1992_42_2_a7,
     author = {Ol\'ah, Rudolf},
     title = {On positive solutions of nonlinear retarded differential equations},
     journal = {Mathematica slovaca},
     pages = {201--210},
     year = {1992},
     volume = {42},
     number = {2},
     mrnumber = {1170104},
     zbl = {0756.34070},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/MASLO_1992_42_2_a7/}
}