@misc{indiciaee154470fdc5e,
  title = {GKS-PC; a Kernel Graphics programming system for IBM-PC and compatible microcomputers},
  author = {Richard H. Balay},
  year = {1993},
  doi = {10.3133/ofr93241},
  url = {https://pubs.usgs.gov/publication/ofr93241},
  note = {Source identifier: ofr93241}
}