1. 1995–1996 Kentucky Coal Facts,1996
2. Correlation of Coal Beds, Coal Zones and Key Stratigraphic Units in the Pennsylvanian Rocks of Eastern Kentucky;Rice;Miscellaneous Field Studies Map MF-2275, US Geological Survey,1994
3. Stratigraphic and Structural Framework of the Carboniferous Rocks of the Central Appalachian Basin in Kentucky;Chestnut;Bulletin 3, Kentucky Geological Survey,1992
4. Modes of occurrence of potentially hazardous elements in coal: levels of confidence
5. Trace Elements in Coal;Swaine,1990