Detailed search strategies were developed for each electronic database in order to identify the studies for inclusion in this review: The Cochrane Central Register of Controlled Trials: Cochrane Library current issue, MEDLINE/PubMed from 1966 to 2010, LILACS from 1992 to 2010 and other electronic databases and grey literature.
Para identificar estudios para la inclusión en esta revisión, las estrategias de búsqueda detallada se desarrollan para cada base de datos electrónica de la búsqueda. The Cochrane Central Register of Controlled Trials: Cochrane Library current issue, MEDLINE/PubMed from 1966 to 2010, LILACS from 1992 to 2010 y otras bases de datos electrónicas y literatura gris.