1. University of Medicine of Petropolis; Department of Clinical Surgery; Rua Almirante Saldanha, 184 Cremerie Petrópolis Rio de Janeiro Brazil 25645-230
2. Universidade Federal de São Paulo / Escola Paulista de Medicina; Brazilian Cochrane Centre; Rua Pedro de Toledo 598 Vila Clementino São Paulo SP Brazil CEP 04039-001
3. Brazilian Cochrane Centre; Rua Pedro de Toledo 598 Vila Clementino São Paulo SP Brazil 04039-001
4. Federal University of Rio Grande do norte; Department of Medicine; Alameda jauaperi 1083 São Paulo Vila Clementino Brazil 04523-014
5. Rua Almirante Saldanha, 184 Cremerie Petrópolis Rio de Janeiro Brazil 25645-230
6. FESP ? Escola Paulista de Medicina; Brazilian Cochrane Centre; Rua Edison 278, Apto 61, Campo Belo São Paulo São Paulo Brazil 04618-031
7. Av. Visconde de Albuquerque 694 ap. 202 Leblon Rio de Janeiro Rio de Janeiro Brazil 22450-000
8. Universitaetsklinikum Duesseldorf, Heinrich-Heine University; Department of General Practice; PO Box 101007 Duesseldorf Germany 40001