@misc{indiciaed11b684a37ab,
  title = {Documentation and application of a method to compute maximum slope and aspect of hydraulic gradients},
  author = {C. M. Johnston and P. T. Harte},
  year = {1998},
  doi = {10.3133/wri984021},
  url = {https://pubs.usgs.gov/publication/wri984021},
  note = {Source identifier: wri984021}
}