Descripción
Notas:Bibliographic Level Mode of Issuance: Monograph
Formato:Mode of access: Internet from the National Library of Medicine and AHRQ web sites. Addresses as of 5/10/04: http://text.nlm.nih.gov/ftrs/dbaccess/ventsum (NLM), http://www.ahrq.gov/clinic/epcsums/mechsumm.htm (AHRQ); current access to AHRQ version available via PURL.