National Coal Resource Assessment (Estados Unidos), & National Coal Resource Assessment (Estados Unidos). (2001). 2000 resource assessment of selected coal beds and zones in the Northern and Central Appalachian basin coal regions (Version 1.0.). [Reston, Va.?]: U.S. Geological Survey.
Chicago Style CitationNational Coal Resource Assessment (Estados Unidos), and National Coal Resource Assessment (Estados Unidos). 2000 Resource Assessment of Selected Coal Beds and Zones in the Northern and Central Appalachian Basin Coal Regions. Version 1.0. [Reston, Va.?]: U.S. Geological Survey, 2001.
MLA CitationNational Coal Resource Assessment (Estados Unidos), and National Coal Resource Assessment (Estados Unidos). 2000 Resource Assessment of Selected Coal Beds and Zones in the Northern and Central Appalachian Basin Coal Regions. Version 1.0. [Reston, Va.?]: U.S. Geological Survey, 2001.