@misc{indiciae8bbcf4d109be,
  title = {A computer program for simulating geohydrologic systems in three dimensions},
  author = {D.R. Posson and G. A. Hearne and J.V. Tracy and P. F. Frenzel},
  year = {1980},
  doi = {10.3133/ofr80421},
  url = {https://pubs.usgs.gov/publication/ofr80421},
  note = {Source identifier: ofr80421}
}