@misc{indiciae1f94511eee9e,
  title = {Computer simulation models as tools for identifying research needs: A black duck population model},
  author = {J.K. Ringelman and J. R. Longcore},
  year = {1980},
  url = {https://pubs.usgs.gov/publication/5221566},
  note = {Source identifier: 5221566}
}