@misc{indiciaebc0b23d97f4b,
  title = {Controlled photomosaic of the Valhalla Quadrangle of Callisto},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1990},
  doi = {10.3133/i1887},
  url = {https://pubs.usgs.gov/publication/i1887},
  note = {Source identifier: i1887}
}