@misc{indiciaec547afc1ba2b,
  title = {POLYGON; program listing},
  author = {B. A. Chuchel},
  year = {1985},
  doi = {10.3133/ofr85233b},
  url = {https://pubs.usgs.gov/publication/ofr85233B},
  note = {Source identifier: ofr85233B}
}