@misc{indiciae398e93ad8b93,
  title = {Map showing bedrock topography and area of occurrence of Madisonville limestone member of Sturgis Formation (Upper Pennsylvanian) beneath alluvial deposits of the Smith Mills Quadrangle, Henderson and Union counties, Kentucky},
  author = {R. L. Norris},
  year = {1975},
  doi = {10.3133/i889},
  url = {https://pubs.usgs.gov/publication/i889},
  note = {Source identifier: i889}
}