title: [The efficiency of natural fertility control: new perspectives].
authors.affiliation: Facultad de Medicina, Universidad de Navarra.
authors.forename: J
authors.initials: J
authors.lastname: de Irala
authors.forename: E
authors.initials: E
authors.lastname: Gómez Gracia
authors.forename: J
authors.initials: J
authors.lastname: Fernández-Crehuet
mesh_terms: D005260:Female; D006801:Humans; D012252:Natural Family Planning Methods / Q000592:standards