@misc{indiciae341dba73b887,
  title = {PTCOUNT - a Fortran-77 computer program to calculate the areal distribution of mapped data points using count-circle methodology},
  author = {William Z. Savage and Jeffrey A. Coe and Ronald E. Sweeney},
  year = {2001},
  doi = {10.3133/ofr012},
  url = {https://pubs.usgs.gov/publication/ofr012},
  note = {Source identifier: ofr012}
}