@misc{indiciaed6f2afcd9a9a,
  title = {Surficial geologic map of the West Thumb Quadrangle, Yellowstone National Park, Wyoming},
  author = {G.M. Richmond},
  year = {1973},
  doi = {10.3133/i643},
  url = {https://pubs.usgs.gov/publication/i643},
  note = {Source identifier: i643}
}