http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
lo que usted necesita saber acerca del ozono y su salud
Also available via Internet from the EPA web site. Address as of 11-14-00: http://www.epa.gov/airprogm/oar/oaqps/airnow/elsmog/index.html; current access is available via PURL.