@misc{indiciae9ee9f59edcb3,
  title = {Ecoregions of the conterminous United States: Evolution of a hierarchical spatial framework},
  author = {James M. Omernik and Glenn E. Griffith},
  year = {2014},
  doi = {10.1007/s00267-014-0364-1},
  url = {https://pubs.usgs.gov/publication/70125309},
  note = {Source identifier: 70125309}
}