@misc{indiciae220c035c4d31,
  title = {User guide for MODPATH version 6—A particle-tracking model for MODFLOW},
  author = {David W. Pollock},
  year = {2012},
  doi = {10.3133/tm6a41},
  url = {https://pubs.usgs.gov/publication/tm6A41},
  note = {Source identifier: tm6A41}
}