@misc{indiciaee39279878b70,
  title = {Polar bear},
  author = {Steven C. Amstrup},
  year = {2000},
  doi = {10.1016/b978-012701235-3/50009-x},
  url = {https://pubs.usgs.gov/publication/87184},
  note = {Source identifier: 87184}
}