@misc{indiciaecc18b6db84b0,
  title = {Reconnaissance geology of the Madha Quadrangle, sheet 18/43 A, Kingdom of Saudi Arabia},
  author = {George Clarke Simmons},
  year = {1979},
  doi = {10.3133/ofr80133},
  url = {https://pubs.usgs.gov/publication/ofr80133},
  note = {Source identifier: ofr80133}
}