@misc{indiciae5e1988b263f1,
  title = {Geologic map of part of the Tyrrhena Patera region of Mars (MTM Quadrangle-20252)},
  author = {T.K.P. Gregg and D.A. Crown and Ronald Greeley},
  year = {1998},
  doi = {10.3133/i2556},
  url = {https://pubs.usgs.gov/publication/i2556},
  note = {Source identifier: i2556}
}