TY  - RPRT
TI  - Correlation chart of Pennsylvanian rocks in Alabama, Tennessee, Kentucky, Virginia, West Virginia, Ohio, Maryland, and Pennsylvania showing approximate position of coal beds, coal zones, and key stratigraphic units
AU  - Leslie F. Ruppert
AU  - Michael H. Trippi
AU  - Ernie R. Slucher
PY  - 2010
DO  - 10.3133/sir20105152
UR  - https://pubs.usgs.gov/publication/sir20105152
ID  - sir20105152
ER  -