@misc{indiciae1a7e9f7014f1,
  title = {Dark material in the polar layered deposits and dunes on Mars},
  author = {Kenneth E. Herkenhoff and Ashwin R. Vasavada},
  year = {1999},
  doi = {10.1029/1998je000589},
  url = {https://pubs.usgs.gov/publication/70021536},
  note = {Source identifier: 70021536}
}