@misc{indiciae196e8fa255e7,
  title = {Aerial surveys of waterfowl production in North America, 1955-71},
  author = {Charles J. Henny and David R. Anderson and Richard S. Pospahala},
  year = {1972},
  url = {https://pubs.usgs.gov/publication/ssrw160},
  note = {Source identifier: ssrw160}
}