Pinelas, SandraFerreira, José M.2015-07-312015-07-312013José M. Ferreira and Sandra Pinelas, Oscillatory retarded functional systems, Journal of Mathematical Analysis and Applications, 285 (2003), 506-527http://hdl.handle.net/10400.26/9535engjournal article10.1016/S0022-247X(03)00421-9