@misc{indiciae90729084276a,
  title = {GSMGRASS: a program to convert a GSM data base into ASCII files that can be imported directly into the Geographic Resources Analysis Support System (GRASS), Part A - Documentation},
  author = {Gary I. Selner and Joseph L. Plesha},
  year = {1990},
  doi = {10.3133/ofr90539a},
  url = {https://pubs.usgs.gov/publication/ofr90539A},
  note = {Source identifier: ofr90539A}
}