@misc{indiciae481db3d0002d,
  title = {GSDIG version 3.0; a program to determine latitude, longitude coordinates or X, Y coordinates using a microcomputer (IBM PC or compatible) and a digitizer},
  author = {G.I. Selner and C. L. Smith and R. B. Taylor},
  year = {1990},
  doi = {10.3133/ofr9080},
  url = {https://pubs.usgs.gov/publication/ofr9080},
  note = {Source identifier: ofr9080}
}