@misc{indiciae45075bea5fa4,
  title = {Small-format cameras and fine-grain film used for waterfowl population studies},
  author = {Edgar L. Ferguson and David S. Gilmer},
  year = {1980},
  doi = {10.2307/3808021},
  url = {https://pubs.usgs.gov/publication/1001696},
  note = {Source identifier: 1001696}
}