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2. National Institute for Clinical Excellence. The guidelines manual. London: National Institute for Clinical Excellence; 2004. Disponible en: http://www.nice.org.
3. The AGREE Collaboration. Evaluación de guías de práctica clínica. Instrumento AGREE. 2001. Disponible en: http://www.agreecollaboration.org/pdf/es.pdf.
4. GRADE working group. Grading of Recommendations of Assessment Development and Evaluations. Disponible en: http:www.gradeworkinggroup.org/
5. Disponible en: http://www.guiasalud.es.