@misc{indiciaea676237e0ace,
  title = {GSREF version 4.0; a bibliographic reference system for the IBM PC and compatible microcomputers},
  author = {G.I. Selner and R. B. Taylor},
  year = {1990},
  doi = {10.3133/ofr90229},
  url = {https://pubs.usgs.gov/publication/ofr90229},
  note = {Source identifier: ofr90229}
}