@misc{indiciae497c21faaadd,
  title = {Evaluation of the matrix exponential for use in ground-water-flow and solute-transport simulations; theoretical framework},
  author = {A.M. Umari and S.M. Gorelick},
  year = {1986},
  doi = {10.3133/wri864096},
  url = {https://pubs.usgs.gov/publication/wri864096},
  note = {Source identifier: wri864096}
}