@misc{indiciae283ad9c54e85,
  title = {A generalized finite-difference formulation for the U.S. Geological Survey modular three-dimensional finite-difference ground-water flow model},
  author = {Arlen W. Harbaugh},
  year = {1992},
  doi = {10.3133/ofr91494},
  url = {https://pubs.usgs.gov/publication/ofr91494},
  note = {Source identifier: ofr91494}
}