@misc{indiciae7ea2531b956d,
  title = {Correlation of coal beds, coal zones, and key stratigraphic units in the Pennsylvanian rocks of eastern Kentucky},
  author = {Charles L. Rice and J. Hiram Smith},
  year = {1980},
  doi = {10.3133/mf1188},
  url = {https://pubs.usgs.gov/publication/mf1188},
  note = {Source identifier: mf1188}
}