@misc{indiciaea1125dccce44,
  title = {MAPTOPS (version 1); a program to retrieve formation tops},
  author = {C. J. Wandrey and R. C. Obuch},
  year = {1990},
  doi = {10.3133/ofr89575},
  url = {https://pubs.usgs.gov/publication/ofr89575},
  note = {Source identifier: ofr89575}
}