@article{EJDE_2003__2003__a33,
     author = {Boulite,  Said and Maniar,  Lahcen and Moussi,  Mohammed},
     title = {Non-autonomous retarded differential equations: the variation of constants formulas and the asymptotic behaviour},
     journal = {Electronic journal of differential equations},
     year = {2003},
     volume = {2003},
     zbl = {1060.47044},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2003__2003__a33/}
}