http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Oil and gas in Bond, Macoupin, and Montgomery counties, Illinois
Illinois coal mining investigations (Cooperative agreement)
by Raymond Blatchley; work done in cooperation with Illinois coal mining investigations, and U. S. Geological survey.
Bulletin (Illinois State Geological Survey) ; no. 28