@misc{indiciaed5f866583f6a,
  title = {Aerial estimation of the size of gull breeding colonies},
  author = {J.A. Kadlec and W.H. Drury},
  year = {1968},
  doi = {10.2307/3798973},
  url = {https://pubs.usgs.gov/publication/5220558},
  note = {Source identifier: 5220558}
}