http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Title from PDF caption (viewed Mar. 6, 2009).
Mode of access: Internet at the FAA web site. Address as of 3/6/09: http://www.airweb.faa.gov/Regulatory%5Fand%5FGuidance%5FLibrary/rgAdvisoryCircular.nsf/0/f28d235dfd44721e862569f1005f7f10/$FILE/ac-121-25.pdf ; current access available via PURL.
United States. Federal Aviation Administration.