@misc{indiciae548fc4329983,
  title = {PCCONTUR VERSION 1.0 : a microcomputer general purpose contouring program, Part D - Plot system source code and library disk},
  author = {Richard H. Godson and Robert E. Bracken and Michael W. Webring},
  year = {1988},
  doi = {10.3133/ofr88593d},
  url = {https://pubs.usgs.gov/publication/ofr88593D},
  note = {Source identifier: ofr88593D}
}