@misc{indiciaea50fce429aa0,
  title = {Mathematics and mallard management},
  author = {L.M. Cowardin and Douglas H. Johnson},
  year = {1979},
  doi = {10.2307/3800632},
  url = {https://pubs.usgs.gov/publication/1001686},
  note = {Source identifier: 1001686}
}