2015-02-272015-02-2720051130-0108http://scielo.isciii.es/pdf/diges/v97n7/carta4.pdfhttp://hdl.handle.net/11441/22913spaAtribución-NoComercial-SinDerivadas 4.0 Españahttp://creativecommons.org/licenses/by-nc-nd/4.0info:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccesshttps://idus.us.es/xmlui/handle/11441/22913