@misc{indiciae1fd170e115c0,
  title = {Geologic maps of the Olympus Mons region of Mars},
  author = {E. C. Morris and K. L. Tanaka},
  year = {1994},
  doi = {10.3133/i2327},
  url = {https://pubs.usgs.gov/publication/i2327},
  note = {Source identifier: i2327}
}