http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Oil and gas resources of the United States
Title from title screen (viewed on July 12, 2004).
"Last modified 17-Oct-2002"--USGS Energy Fact Sheet index.
Series and numbering from the USGS Fact Sheet home page.
Electronic resource] : the 1995 National Assessment.
Mode of access: Internet from the USGS web site. Address as of 7/12/04: http://energy.usgs.gov/factsheets/95assessment/95assessment.html; current access is available via PURL.
Fact sheet (Geological Survey (U.S.)) ; FS-97-018