@misc{indiciaeafe060dc80a7,
  title = {GSDIG version 2.0; a program to determine latitude/longitude coordinates, and GSDXY version 1.0, a counterpart program to determine X, Y coordinates, using a microcomputer (IBM PC or compatible) and digitizer},
  author = {Gary I. Selner and Cole L. Smith and Richard B. Taylor},
  year = {1988},
  doi = {10.3133/ofr88428a},
  url = {https://pubs.usgs.gov/publication/ofr88428A},
  note = {Source identifier: ofr88428A}
}