@article{EJDE_2010__2010__a18,
     author = {Lakrib,  Mustapha and Sari,  Tewfik},
     title = {Time averaging for ordinary differential equations and retarded functional differential equations},
     journal = {Electronic journal of differential equations},
     year = {2010},
     volume = {2010},
     zbl = {1201.34128},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2010__2010__a18/}
}